Talk:IBM PCjr

Should I take pictures
Should I take pictures of my PCjr? Mine is a expanded one however. --Texnofobix


 * A picture would be great! moink 02:59, 28 February 2006 (UTC)


 * Agreed iambk


 * I need to get better lighting and this isn't stock, but here is mine. File:PCjr expanded.jpg --Texnofobix 02:28, 26 April 2007 (UTC)

Discussion cleanup?
Since the exchanges between Bptdude and Trixter seem to be done, can they either be removed or edited down a bit? Misoman 09:03, 7 February 2007 (UTC)
 * I'd love that, but unfortunately doing so is against some wikipedia guideline that I can't remember at the moment. --Trixter 20:39, 7 February 2007 (UTC)
 * Talk_page_guidelines discourages editing or removing comments, but allows it if agreed upon by those involved. So I guess it depends on whether Bptdude feels there's value in keeping it all intact. There might be a couple snippets worth preserving, but with POV and grammar issues resolved I think much could be trimmed. By the way, for future reference, I hereby give permission for anyone to delete my comments in this section when they are no longer relevant. I don't want this section getting stuck here forever, too. Misoman 19:31, 12 March 2007 (UTC)

Wow, been awhile since I visited here. Yeah, if somebody wants to cleanup the discussion, they can edit my stuff out. The pages seem stable, and this PCjr wiki page was meant by me to just be a not way too serious page, like so many of the other pages in Wiki. Let's keep it brief and well done, for all of us who have a special place in our techncial memories for the only computer we could actually take a soldering iron to, and actually mod it, without screwing it up, or needing an electronics lab. — Bptdude 08:11, 7 May 2007 (UTC)

More info
The Tandy 1000's enhanced video modes were functionally identical to the PCjr, but differed slightly in how software addressed them. The same was true of the sound, since the Tandy also used the same sound chip, which was also used in the TI-99/4 and 4A computers. Rivaled the Atari POKEY? No way! Three simultaneous tones and one noise, with the noise being a choice of waveforms or 'white', which sounded like radio static.

Simple hardware modifications to the mainboard allowed a PCjr to run nearly all Tandy 1000 software with the enhanced video modes and sound.

IBM also sold a speech module, using the same TI speech chip in the speech module for the 99/4A, but IBM's implementation was much more limited than TI's, with very little PCjr software written to use speech.

3rd party upgrades often added a 'second story' on top of the main case, using a special sidecar expansion to connect the upper floppy drive bay and circuit board. These upgrades were mostly for expanding the RAM to 512K or 640K in addition to the second floppy bay. Some included other peripherals in the additional space since the RAM expansion didn't use anywhere near the full height of the expansion case.

The internal modem from IBM was pitifully slow. ISTR that at least one 3rd party made a 14.4 internal modem, but it may have required mainboard modifications to implement DMA.

The system had a 'last gasp' in Japan and Australia as the IBM PCjx in a black case (update: I've seen this in a white case) with two 720K 3.5" floppy drives and an extended keyboard. http://popcorn.cx/computers/ibm/pcjx/

Comment from iambk: The system could barely handle a 2400bps modem and I don't think a 14.4kbps internal modem was ever made for the PCjr.

The 300 baud modem was useless, really. I had a Hayes 1200 that worked fine on the serial port. I still have that modem, as it is unique also, in that it can take ascii text from the serial port and output morse code in standard audio, by flipping a toggle switch.
 * Just for curiosity's sake, are you sure that the toggle switch was for switching to Morse? I had a Hayes Smartmodem 300, and Morse code was built-in to the Hayes command set with no need for a physical switch over. Requiring a switch seems like a step backwards in terms of design. -- Misoman 00:09, 9 January 2007 (UTC)

I did bring my PCjr into work at the phone company and replaced the DEC paper teletype with it. The DEC terminal was the console to a PDP 11/44 with lots of big washingmachine-sized disk drives, etc. The PCjr was pure magic next to it. By using the computer and a PC program I copied from somebody running a PC at work { something all other PCjr home computers couldn't do, use most PC software}, I was able to be the first in the office to have a computer screen at my desk. The interface was 9600 baud and worked fine in the PCjr serial port. Later I was able to use the cartridge BASIC for PCjr to program in and out of the comm port to automate some minicomputer tasks and to capture output to my PCjr floppy disk, that I was able to run reports on the output of DEC commands.

By-the-way, 14.4kbps could have been a much later third party product. But 14.4 modulation didn't exist until almost 10 years after the PCjr was introduced. —Bptdude 02:14, 13 August 2006 (UTC)

PC JX
Article should make some mention of the PC Jx. Bastie 03:27, 24 February 2007 (UTC)
 * Separate article exists at IBM JX. 2fort5r (talk) 10:36, 17 August 2009 (UTC)

Capabilities
"offered built-in color graphics and sound comparable to or superior to other home computers of the day." - I think we've established that this isn't true when compared to the C64 especially --MartinUK 19:05, 20 May 2006 (UTC)

^^ Updated.

Failure in the marketplace
Failure in the marketplace

I removed the comment about the wireless feature of the keyboard. I remember articles in PCjr magazine about this. They were trying to use the keyboard from accross the room. This is typical of the gap between the designers and the wildly expectant market. In fact the keyboard worked great from only a few feet away, and the infrared eye was right in the front of the computer, usually less than a foot away. — Bptdude 01:58, 13 August 2006 (UTC)

I'm with you. The wireless keyboard was the one thing about the PCjr that worked well.70.88.213.74 (talk) 16:36, 12 August 2010 (UTC)

The following blog makes interesting reading:http://www.filfre.net/2013/07/popcorn-and-peanuts/ The author makes the point that the PCjr wasn't so much a commercial failure (IBM sold half a million from launch, which was no mean feat), but rather the margins were much lower than higher end machines such as the PC/AT. John a s (talk) 00:19, 22 November 2014 (UTC)

External link for pics
can somebody more wiki savy please help make links to some of the graphic examples in the following link, for the main article page?

http://www.oldskool.org/shrines/PCjr_tandy

Trixter edits to undo mine on article features
Hey Trixter,

I undid your edits, please leave mine there.

First topic
mine:

The PCjr had a limited amount of business software available on cartridge, including a PCjr version of Lotus 123 spreadsheet. The cartridge would be plugged in from the front, the computer would reboot, and automatically run, with the ability to load and save data by means of the floppy drive. Dedicated computers that run common office software have not been seen since.

yours:

The PCjr had a limited amount of business software available on cartridge, including a PCjr version of Lotus 123 spreadsheet. General usage entailed plugging in the cartridge from the front, prompting a reboot of the computer; the software would run automatically, with the ability to load and save data by means of the floppy drive.

my comment:

We don't need to say "General usage". You plugged in the cartridge, the computer rebooted. There was no other option. It was not software, either, it was firmware. And unless you can name me systems that have no OS but will run Microsoft Office from firmware, please leave my comment about "not been seen since" alone.


 * My issue wasn't with "not been seen since", my issue was with "Dedicated computers that run common office software" which is awkward and not really correct. If you want to say that PCs that run cartridge software haven't been seen before or since, that's correct. But there have most definitely been "dedicated computers that run common office software" (dedicated word processors, most PDAs, etc.) --Trixter 15:15, 21 August 2006 (UTC)

Second topic
mine:

The PCjr had two joystick ports. There were only a few games that took advantage of this, but this allowed two player games, similar to modern game consoles. This is a feature not available on major brands computers since.

yours:

The PCjr had two joystick ports. There were only a few games that took advantage of this, but this enabled two-player games, similar to modern game consoles.

my comment:

Unless you can name even one major computer brand that sells a system with two joystick/game ports, please leave this comment alone.


 * Tandy 1000 series, which lasted until at least 1990 and was most definitely more popular than the PCjr. Also Amstrad, in the UK. So your comment was technically incorrect, which is why I fixed it. Should I fix it again, or do you want to? --Trixter 15:17, 21 August 2006 (UTC)

Third topic
mine:

The PCjr had a lightpen port. The lightpen worked as a mouse replacement. It was not very common, and the port was later used in combination with the serial port to use an optic mouse, which worked very well. Most PC mice for years used mechanical balls and optic mice are now more the convention.

yours:

The PCjr had a lightpen port, which worked as a mouse replacement. It was not very common, and the port was later used in combination with the serial port to drive an optical mouse, which worked very well.

my comment:

The lightpen and the lightpen port were two different things. The lightpen port was used as an input port for some other devices. The optic mouse was similar to those used in workstations with a special reflective pad that had a grid. That PC's mechanical balls for years before only now converting back to optic is true and worth mention about the PCjr design. Please leave comment alone unless you can justify why.


 * What you originally wrote doesn't make sense. Are you saying that a mechanical mouse that used the lightpen port is the same as an optical mouse? That's obviously not true... Are you saying that PCs didn't use optical mice until recently? That's also not true; in fact, the first widely-available mouse for the PC was from Mouse Systems and was optical (used the metallic pad you metion) and was available before the first Microsoft mouse (mechanical) was. So I edited that passage because I'm not really sure what you're trying to prove. --Trixter 15:32, 21 August 2006 (UTC)

Fourth topic
mine:

The PCjr could be purchased with full manuals that included BIOS source code and all hardware schematics. This made for the popularity of hobby/home modifications and a number of small shop hardware upgrade companies, eventually being absorbed by PC Enterprises. Such open design is unheard of in modern systems.

yours:

The PCjr could be purchased with full manuals that included BIOS source code and all hardware schematics. This made for the popularity of hobby/home modifications and a number of small shop hardware upgrade companies, eventually being absorbed by PC Enterprises.

my comment:

such open design is unheard of in modern systems. You can't to to Circuit City or Walmart and purchase the firmware manuals and detailed schematics of any computer system you want to own. The PCjr was meant to be a hobby system, and the release of such detail was not seen as any threat, as it was a unique system design, not a PC clone. We live in a world of open software in a battle with central corporate software. We might again see the day of open hardware. In the meantime, my comment is true, unless you want to provide examples of shrinkwrapped retail documentation of any major brand of computer.


 * First of all, the PCjr tech reference was a seperate product; what you originally wrote implied that it was bundled with it. You also imply that the PCjr tech reference was significantly different from other personal computers of the time, yet the 5150 also had a full tech reference available, as did the Apple II and other personal computers. Also, the statement "Such open design is unheard of in modern systems" is ludicrous because everything you want to know about your PC, at the lowest levels, is available for free on the web. Not necessarily from the manufacturers, but from many different sources. Finally, the PCjr was not meant as a "hobby" system, it was meant as a family system -- there is a very big difference between the two.
 * Full disclosure of the hardware was significant, I agree, but you need to state it like that, instead of trying to make some sort of social comment on modern computing. Wikipedia is about objective facts, not POV commentary.--Trixter 15:49, 21 August 2006 (UTC)

Fifth topic
mine:

The two front cartridge slots were used not only for stand alone bootable programs, that didn't require an OS, they were also used with third party cartridges to update the system BIOS and other firmware. Multiple patches from various vendors were included on a single combo-cartridge slot. These were used to support add-on hardware, bypass certain limitations of design, and keep up with changing OS requirements.

yours:

The two front cartridge slots were used not only for stand alone bootable programs but also with third party cartridges to update the system BIOS and other firmware. Multiple patches from various vendors were included on a single combo-cartridge slot. These were used to support add-on hardware, bypass certain design limitations, and keep up with changing OS requirements.

my comment:

I'm guessing you think all computers run with an OS or something. This is very much not true, as people dealing withe embedded systems will tell you. In the days of the PCjr, many hacking away at eary versions of PC's, would use Disk Operating Systems { early DOS before the DOS that we came to know existed } to enable hard drive attachments. Production industrial systems would then use the tested software burned onto chips to actaully run. Please leave the comment about OS alone, so people can understant this as a computer that could run with an OS or without it, simply by slamming a game style cartridge in the front or pulling it out.


 * I didn't change your content at all with my edit; I only fixed the awkward grammar! What in my edits caused you to think I was altering the informational content of what you wrote? --Trixter 16:01, 21 August 2006 (UTC)

Sixth topic
mine:

The PCjr had wireless keyboards that could also operate with a telephone style cable. This worked well enough to allow the keyboard to be placed in front of the system to type.

yours:

The PCjr's wireless keyboards could also operate with an RJ11 telephone-style cable. This enabled the keyboard to be used like a traditional keyboard, saving the battery drain used when in wireless mode.

my comment:

The commotion about the keyboard and PCjr was huge and was so much a part of the system's termination, I want the wording very specific. It was not an RJ11, if you want to be technical and nit-pick. It had a connector on only one end like a telephone and the modulations and signals were completely not analog audio transmit/receive. My comment is to state that the wireless keyboard worked just fine in front of the computer, though morons complained when it would not work from accros the room, like a TV remote. I did not intend to comment about the battery drain in this paragraph.


 * The cable used actual RJ11 jacks, and you wrote telephone-style cable, so the RJ11 edit is valid and correct. Also, if the point of your content was to make a comment on how well the wireless keyboard worked, you did not convey that in your content at all and should mention it specifically. (By the way, not working from across the room like a TV remote was indeed a valid complaint, since it was a major advertising point of the PCjr! The PCjr was marketed as being perfect to connect to the family television, like most personal computers it was competing against. Having a wireless keyboard was a major selling point for people who wanted to do this.) --Trixter 16:07, 21 August 2006 (UTC)

In closing
In general, I think I go back a bit further than you in computer history. The PCjr did have a number of concepts that for whatever reason didn't go forward, and to have owned one, which I did, is to wonder why.

I have a feeling you come from a place in current computer industry that makes you defensive, for some reason. This is just a PCjr article. If you want to add your own new experiences, fine. Don't start a revert war over this. — Joe (Bptdude) 04:50, 19 August 2006 (UTC)


 * Joe: You write things like "never before seen or seen since" for several PCjr features which are simply untrue. I have commented on them above. You wrote "add your own new experiences", but wikipedia isn't about what you experienced or remembered, it's about objective facts. Please keep this in mind; you wrote many subjective comments (what the wikipedia comunity calls "POV" (point of view)) which are discouraged.


 * For the record, I own 5 PCjrs and have been using IBMs since the 5150. My passion for the PCjr is also evident in how *accurate* I want this page to be, which is why I made the edits in the first place.


 * All this aside, my main motivation was correcting your grammar and rewording sentences to be less awkward. Will you revert my edits if I correct your grammar? --Trixter 15:03, 21 August 2006 (UTC)

Hey Trixter,

Thank you for a nice response. I've been a little fed up with people in wikiworld who swoop in to make trivial edits on things they really have no expertise in, sometimes removing valuable information because they don't understand the context. I'm glad to hear you are a PCjr owner and as such probably about as much expert as anybody else to edit this.

Of course you can edit grammer, etc. I would appreciate it.

On some issues, yes, you have to reference other sources, but I truly believe personal observations and real world experience do count and add great value to wiki, adding greater value than can be found in traditional references. If I was in Vietnam and wrote what I personally saw about the effect of agent orange on banana crops, would you want me to remove it because I couldn't reference some academic source? Wouldn't it be enough to reference myself as having actually been there, where and when, what unit I was with, etc?


 * No, it wouldn't, because your personal account isn't verifiable by other sources. Nothing personal against you, but wikipedia cannot contain unverifiable information; otherwise, a multitude of whack jobs would corrupt it absolutely. --Trixter 05:57, 22 August 2006 (UTC)

Anyways, I would agree it would not be appropriate to give an opinion, like "PCjr was the best computer ever", but stating PCjr had concepts such as built in twin joystick/game controller ports not seen on PC's since is not an opinion, and is true to the best of my knowledge. If you think about it, it really is odd PC's didn't have such things, when game controllers, so popular do! This is the point. The PCjr really was an odd mix of computer and features seen more often on game controllers. That's what I was trying to explain.


 * Unfortunately for your contributions, it is *not* true (several other PCs had dual joystick ports, as I previously pointed out). I agree it's odd that several great ideas introduced by the PCjr didn't perpetuate to other clones/platforms, but that's no reason to have inaccurate information in the article. --Trixter 05:57, 22 August 2006 (UTC)

I do miss my PCjr. I think I had all the best upgrades, spending way too much time and money on it. In the end I even had twin 200 meg scsi drives and vga and did a lot of software development work on it. I had a C compiler that fit on a 720 K floppy, which when I loaded the libraries into the RAM disk would compile with amazing speed. I miss having a computer I could take my soldering iron to myself and still have it work after. *smiles*

I really don't want any grief over something in wiki as below the radar as PCjr. It is kinda why I edited it, instead of something with a lot more profile.

Good to see another old computer salt though. Yeah, I go back to programming BASIC from the mid 1970's on Wang 2200's.

I do think it odd about some later add-on features never made it to PC's. For example, a very inexpensive option I added was a watch battery tiny clock/calendar that was put piggyback under one of the system chips. This was very clever. But why don't PC's today, even $10,000 servers have the accurate clock with the hardware of a $5 Walmart watch? It is just legacy concepts, I figure. There really isn't any good reason, and modern computers should have an accurate clock.

If you studied the PCjr concept, you might wonder why nobody has OS independent games. You might think of using a 4 gig USB memory stick to book the computer and play something that was hardware intensive, not needing Microsoft software. When the computer OS was down because of viruses, you could still boot to stick. To study the odd features of the PCjr does have value, or that is my opinion. These opinions are not in the article, though I have many. I kept it to objective first hand observations. I think that is valid for some things in wiki.


 * Again, unfortunately, your opinions are indeed in the article. I'm going to make several progressive edits over the next few days, maybe one a day, that corrects the inaccurate information. This should be much easier to debate and/or correct than one giant edit. I promise to try very hard to include the spirit of your content if I edit more than just grammar/spelling/etc. But I really must keep the best interests of the article in mind -- I love the PCjr too, which is why I desperately want the article to be as perfect and accurate as possible. --Trixter 05:57, 22 August 2006 (UTC)

Bptdude 01:46, 22 August 2006 (UTC)

Verifiable accounts?
Trixter, you said "No, it wouldn't, because your personal account isn't verifiable by other sources."

are there such things as verifiable accounts for people to enter stuff in wiki? — Bptdude 05:32, 26 August 2006 (UTC)


 * Check Verifiability. — Trixter 19:35, 31 August 2006 (UTC)

Third-party mouse using serial port and lightpen port
i removed the citation needed comment for the line about a mouse was available that used the serial port and lightpen. trixter, was that you? i found a site called oldskooler where you yourself proclaimed knowledge about the company that made it, Mouse Systems. i actually owned one and used it for almost ten years. i'll leave it to you to have fun traking down mouse system's PCjr mice. it's really there, trust me. it required a special reflective pad that was silver colored with dark blue grid lines on it. it was very similar to the mouse i used on old solaris systems, which is why i liked it. — Bptdude 06:41, 28 September 2006 (UTC)


 * The citation wasn't there to dispute the optic mouse -- I owned a Mouse Systems mouse as well. The citation needed was for the comment "The lightpen port was later used in combination with the serial port". That is the part that needs citation, since every Mouse Systems mouse I ever saw had only a serial port. Can you confirm the PCjr version also needed to use the serial port? If not, that item should be removed, or at least have the citation part put back on. --Trixter 18:41, 28 September 2006 (UTC)


 * I was bored enough to try to find the reference on the web and couldn't. I did find the gentleman who invented the optical mouse, Steve Kirsh, who founded Mouse Systems and emailed him, but he wasn't much help, and didn't seem in the mood. I have a feeling Mouse Systems had an unpleasant demise. I did read a bit about Mouse Systems mice. The reason my PCjr mouse was so much like the one on the Sun workstation, is that they were both Mouse Systems mice, and bacsically the same thing. All Mouse Systems mice required an external power source. This was done on PC's by a special adapter that piggybacked into the keyboard port. I'm assuming then my Mouse Systems PCjr mouse was just using the lightpen port for power. If this is not familiar to you, how did yours work? — Bptdude 21:32, 28 September 2006 (UTC)


 * I never had a PCjr one. I did some research of my own and found that the PCjr version did indeed connect to the lightpen port. However, it did so for the +5vdc power, not because of anything "optical" about it. So the citation is not needed.--Trixter 18:25, 29 September 2006 (UTC)

General article comments
I consider myself to be an expert on the Jr. There are a few problems in the write-up as is, but instead of just editing first and defending later I'll make my points here.

Light pens and mice are not equivalent. A mouse, whether optical or not, is a completely different animal than a light pen. A light pen senses the video retrace on the screen and uses timing to figure out where the user was pointing to on the screen. A mouse provides input based on the amount of movement in two directions.

The mice solutions that used the light pen port and the serial port did so only as a source of power. You could have picked up that voltage from anywhere else, including an external wall-wart. Other adapters used the light pen port for power as well because it was there, and the chances on having a light pen were pretty slim. (Light pens were not popular, despite the built in support for them in the hardware on this machine and other machines.) { Bptdude ... there was a light pen, though I don't know anybody or application that used it. There is much about this in the article, it could be shortened. What I had, was a Mouse Systems optical mouse, that used the light pen port for power, and the serial port for communication. Edit the comments or article to this, if you like. }

The cartridge ports on the Jr have two functions: to add ROM BIOS extensions, or to override the system BIOS. What you put in the ROM BIOS extension or how you overrode the system BIOS is what made a cartridge special. The typical use was for user applications, be they games, Colorpaint or Cartridge BASIC. More creative uses included adding hard drive boot code, altering the system BIOS to fix BIOS bugs, and interfacing I/O devices such as clock chips.

PC Enterprises had 'the Combo Cart', and it included several of their utility cartriges in one package. It was all their product or products they had licensed. The text writeup gives the impression of a Swiss-Army knife type cartridge incorporating several vendors code, which is incorrect. {Bptdude ... there were only two slots, and many small patches. PC Enterprises did put multiple patches and mods, some their own, some the bought out, on a single cartridge, so you could run them all. So, wasn't like a Swiss Army Knife? }

Even without Cartridge BASIC, the machine had Cassette BASIC built in.

No interpreted BASIC is going to be fast, or near the speed of compiled BASIC. The Jr was faster at accessing ROM than RAM in some cases, but even that is never going to give interpreted BASIC an edge over compiled BASIC. Somebody should get that comment out of there. { Bptdude ... the IBM BASIC compiler that would run at the time of Jr's release was crud, and the cartridge would run faster, for whatever technical reason. MUCH MUCH faster was the Turbo Pascal that compiled, and that is what we used in the phone company. The compiled code would run on the PC, as long as you avoided the "peeks and pokes", that, well, lots of people just couldn't help but use. I personally got a copy of 'Mix C' that would fit in the RAM drive of a years later highly modified Jr. This made compiling very fast, and this code ran faster than any I used on Jr that I could compile on it }

Nobody put a 14.4K modem in the machine's internal modem slot. SCSI adapters, 2nd diskette drive adapters, etc. But never a modem that fast. The poor machine had a hard time keeping up with 2400 bps due to the use of the NMI interrupt for keyboard deserialization. It could do 9600bps if you used assembler, didn't touch the screen, disk or keyboard, and sacrificed a goat before your transfer. The fastest internal modem I have proof of is a 2400 Hayes compatible, marketed by PC Enterprises. (Of course ...) { Bptdude ... the internal modem really was another piece of crud, even at the 300 baud rate, or whatever it was, I can't remember now. I did use a 9600 baud modem, on the serial port. The trick was to use the CTS/RTS hardware handshaking on the RS-232. I think I as using Procomm software, but it could stop and start the signal, as needed. So, yes, you didn't really get full 9600, but it was pretty good. }

Onto more philosphical issues ...

I've contributed to this article in the past anonymously - I registered so that I could start this dialog. Wiki should be providing objective facts. There seems to be too much editorializing about why the Jr was a failure in the marketplace. The article would be better served by stating what the machine was and its history, and leaving the subjective stuff that isn't easy to substantiate elsewhere. The comment about the keyboard being enough to sink the machine is a perfect example of this. { Bptdude ... if you lived during this time, aware of the industry, you would remember, all most people knew about Jr was the reputation of the keyboard. Replacing it, didn't help, because by then, it was too late. }

At what point should a Wiki article defer to a better source? Quite honestly my web site on the PCjr is a far better source of information about the machine, and always will be unless it gets copied here wholesale. Using external links is not a bad thing. I understand the mission of Wiki and the desire to have the information in a place where it will always be available, but an encyclopedia is supposed to present an overview, not something overly detailed. If you look up FFT you get the general outline of what a Fast Fourier Transform is, not the complete body of work related to deriving and computing FFTs.

The technical content of this article is fine - it is a good overview that meets the purpose of an overview. The editorializing should be excised. But when we start getting into discussions of which particular modems were available and which particular software titles were on cartridge, we might be crossing the line from a good entry in an encyclopedia to overkill on detail.

(bptdude): "The cartridge BASIC for the PCjr gave the advantage of a real programming language always ready without taking up system memory, as it was firmware, with its own address space. It would interpret on the fly with speeds close to what could be achieved with use of the IBM BASIC compiler, partially due to the fact that code hosted in ROM executed faster than code stored in RAM. This made the PCjr an ideal development platform for BASIC programmers doing ad hoc data processing."


 * yes, this was me. In theory, compiled code would be faster than a firmware intepreter. Nice theory. I own and used the PCjr for lots and lots of programming, from jrBASIC, to TurboPascal {which worked quite nice}, to a small C compiler. I used the IBM BASIC compiler quite a bit, and anybody who did, will tell you it was crap. The firmware BASIC was pretty close to compiled for all practical purposes for on-the-fly scripting type stuff. The point about the PCjr was that it had the language always available while DOS was running, without taking up additgional resources or needing to load from media into any RAM. This really was slick. I'm surprised modern PC's don't have Java or C wired on the motherboard. — Bptdude 05:20, 11 October 2006 (UTC)

"The two front cartridge slots were also used with third-party cartridges to update the system BIOS and other firmware. Multiple patches from various vendors were included on a single "combo-cartridge" used to support add-on hardware, bypass certain limitations of design, and keep up with changing OS requirements."

yes, I wrote that too. There were actually a number of combo cartridges with various mixes you could get. Yes, PC Enterprises sold them, and having licensed them, did sell stuff developed and sold by other people. It may have been confusing in the article, but I'm think you may be a bit overmuch on the comments.

I'm sure you have a very nice website dedicated to this. I'm sorry if the Wiki article seems to be encroaching on your project in level of detail.

I don't see reference to "14.4" modem anywhere in the article. Did I miss it? I had a 9600 baud serial card that went into the internal slot for the modem. It worked and you could attach a 14.4 or 32k modem if you wanted to. The faster the phone line side the better, and the serial port could be slowed down to 4800 or whatever and with hardware handshaking there was no loss of data from interupts. Not that I ever noticed. It worked well enough with point-to-point dial-in connections, and for many of us from that era, that meant dialing in to work, to connect and get back out on the early Internet, in text mode, of course.

We already finished the light-pen, mouse discussion. Thank you for rehashing the comments we already posted. — Bptdude 05:32, 11 October 2006 (UTC)

oh yes, the marketing disaster and quick end of PCjr. This was all very much a part of the history of this computer, as can be documented in many many trade publications and main media articles. Of course mention should be made of it. — Bptdude 05:35, 11 October 2006 (UTC)

Mbbrutman

Quoting ...

"It would interpret on the fly with speeds close to what could be achieved with use of the IBM BASIC compiler, partially due to the fact that code hosted in ROM executed faster than code stored in RAM."

The BASIC compiler might generate bad code, but there is no way that anybody can favorably compare the speed of the interpreted BASIC in ROM vs. the compiler generated code. It's just not reasonable. This statement is bogus and should be removed from the writeup. I can take *any* program interpreted and compare it to the compiled version, and the compiled version will be far faster.

Also, all IBM PCs of the era had BASIC built in. The versions of BASIC that came on the DOS disk just wrappered the built in Cassette BASIC to provide DOS support. The cartridge BASIC works much the same way - it extends the built-in Cassette BASIC. So while this is a nice feature, it's not really special compared to other IBM products of the time. In fact, having to shell out $75 for the cartridge BASIC was kind of odious when you couldn't compile it and the DOS BASIC.COM and BASICA.COM would provide most of what people needed.

Name another vendor of a combo cartridge for the PCjr besides PC Enterprises.

The 14.4 modem comment came from what I read in this discussion. IBM clearly states in the technical reference manual that the machine can't reliable do over 2400 bps. I can connect to a 56K modem if I like, and run the port at 9600 bps even. But heaven forbid data actually comes in at that speed. As I said, the machine will drop bytes if you use the diskette, keyboard or BIOS routines to right to the screen. That's not reliable data transfer, and it confirms what IBM engineers said in the book.

Yes I rehashed the light pen discussion. It didn't sound like all parties were convinced.

As for the success in the marketplace discussion. There are 10 paragraphs describing the machines demise, and nine bullet points describing it's technical features. Doesn't that seem lopsided to you? The bit about the keyboard being enough to sink the machine is bogus as well - far too much editorializing, and it's not even close to right. The price and the lack of expandability killed the machine. The keyboard was actually a bright spot - it was fixed, there were 3rd party keyboards available, you could even put a PC keyboard on the machine with an adapter, and the BIOS has 83 key keyboard support built in.

And now, back to Wikiality .. Mbbrutman


 * Gentlemen: First, learn to quote and indent properly because it's difficult to tell whose conversation belongs to whom. See this very text in the editor for an example.
 * Secondly, I believe that some history regarding the failure in the marketplace is necessary, because the PCjr should have been a success but failed due to various issues not considered by the design and marketing teams. It is definitely historically relevant, including a comparison to the Tandy 1000 which cloned it and was successful. However, the existing article reads like an essay on the death of the PCjr, which is not appropriate; see WP:NPOV for justification. --Trixter 17:09, 11 October 2006 (UTC)

All I can tell you about the modem thing, is that at the time it was important to get the serial board when it had the buffered Uart chip and connecting to the modem at 9600 baud was never an issue. I never dropped data or had problems. The hardware handshaking worked well and I'm assuming would just pause the data when needed. It worked great. Whatever you are reading, I actually did this for a long time, and I had no issues.

As for the cartridge issue, I can see you are completely missing the point. The first compiler from IBM for BASIC was horrible, but that is not the point. The cartridge was required to use IBM BASIC from DOS. And having a compiler on floppy was a pain, as it had to load, which was very slow, each time you wanted to try another interation of program change, which for people like me, was about every two minutes. It also took up precious RAM, and couldn't really be done if you were in the middle of other things and had an application floppy loaded and were just shelling out to DOS. Again, I'm not here to argue the speed of compiled code versus interpreted code. But if you programed on the PCjr, you would understand the overall speed and convience of having the interpreter available at any time without memory cost or grinding the floppy. I don't know what else to say. If you don't get this, you just never programmed code enough to get this.

The marketing thing? It is all people really remember about the PCjr, and much of it is incorrect hype. Historically, the marketing disaster is a part of PC history. — Bptdude 10:35, 13 October 2006 (UTC)

Here is a line from the article:

"It would interpret on the fly with speeds close to what could be achieved with use of the IBM BASIC compiler, partially due to the fact that code hosted in ROM executed faster than code stored in RAM."

I don't care if the cartridge was more convenient than a first generation compiler designed before this machine was conceived - that is not on the page. The statement says that the cartridge could interpret BASIC close to what could be acheived with the compiler. That is completely bogus.

Second line from the article:

"Multiple patches from various vendors were included on a single "combo-cartridge" used to support add-on hardware, bypass certain limitations of design, and keep up with changing OS requirements."

This is inaccurate. PCE made the only combo cartridge. Name another.

I'll rephrase later tonight. — Bptdude 01:10, 15 October 2006 (UTC)

Well, I made the updates, and yes they are improvements and more accurate. Thank you.

One trivia note. In the early days of my PCjr, using just the intenal serial port, I owned a 1200 baud Hayes modem. Designed somewhat with a hobbist in mind, like the PCjr itself, it has the unique feature of modems, in that I could flip a DIP switch, and the output would change from analog fit for a telephone line, trying to talk to another modem, to standard audio out signal sending Morse code. I played with this a couple of times sending the output out over a ham radio transmitter.

09:14, 18 October 2006 (UTC)

I found my old Hayes modem and manual in the shed this weekend,and I remembered I wasn't quite accurate on the Wiki. It wasn't a DIP switch, it was modem commands. The modem was designed to send FSK analog type. We sent morse code by using a special feature designed to meet an FCC requirement to station identify. The modem could send morse code out the FSK modulation, but you had to not only send the special modem commands, but had to send the characters " - " and " . "

We used the PCjr to take text, and using a Basic program I wrote, convert any text file or live typing to the required Hayes commands for dots and dashes. We would send on one frequency, and the other folks would send on another, so we were full duplex. The modem/computer couldn't receive morse code, but could send with a purely perfect 20 words per minute, which is pretty fast in HAM.

Ahhh, memories.... good times!

I even found the original PCjr morse code program I wrote. It really is a shame modern computers don't come with a simple compiler of some sort, made to play with the hardware.


 * smiles* — Bptdude 08:29, 7 May 2007 (UTC)

Power supplies
There were two versions of the internal power supply board. One was 7 inches long and rated for only 33 watts. The other was 10 inches long and rated for approximately 46 watts.

Hardware hacks
The PCjr was a very hackable system. 3rd party developed upgrades were created to make the PCjr's enhanced video modes and TI sound chip compatable with how the Tandy 1000 computers addressed them. Another hardware hack that involved adding parts, cutting PCB traces and soldering enabled the stock IBM floppy controller to support two drives instead of one. The floppy hack and others were detailed in magazines like "Home Computer Magazine" and for PCjr owners who didn't feel up to going at their computer's insides with an X-Acto knife, wire clippers and soldering iron, several 3rd parties offered services to do the modifications. The Tandy 1000 video hack was simple, piggyback one 7400 series TTL chip on top of one on the mainboard for power, cut one trace on the top side of the mainboard and solder three or four wires from the new chip to points on the mainboard. Easy as putting a modchip in an original Playstation. I don't know what all the Tandy 1000 sound modification involved.

There was an even greater number of add-ons and upgrades that were easy to install plug-ins. The NEC V-20 CPU added a small bit of speed to DOS programs and with the 22-NICE emulator the PCjr with that CPU's native Z-80 mode could run CP/M software faster than many dedicated CP/M computers. (In my experience it was much faster than a Xeox 820-II.) There was a battery backed realtime clock which plugged in between one of the BIOS ROM chips and the mainboard, a RAM and FPU upgrade that plugged in between the CPU and mainboard, and something that plugged into the socket for the infrared keyboard reciever. I don't recall what that one was. Yet another modification was a 'thin font' module which plugged in between one of the BIOS ROM chips and the mainboard- with a remotely mounted switch it swapped between the original font and a thinner style that reduced 'blooming' of the characters on the PCjr's monitor, which used a TV style 'slot mask' CRT with large, rectangular phosphor trios. IIRC, this thin font mod was integrated into one or more of the several cartridges produced by PC Enterprises.

Those PC Enterprises cartridges came with different combinations of the hacks and upgrades that were also possible by interposing between the BIOS ROM chips and the mainboard. The 'ultimate' cartridge had them all, and was of course priced higher than the cartridges with fewer hacks. This was possible because the cartridge slots were essentially a direct connection the the BIOS ROM sockets.

Some software cartridges could be used in either slot, but some had to be used specifically in only one slot. Two cartridge programs like LOTUS 123 had them marked Left and Right.

The PCrj's monitor bears nearly as much blame for the computer's market failure as does the chicklet keyboard. By using a cheaper, television quality, CRT IBM saved money but ensured many users would get eye strain trying to focus on its blurry characters in 80 column text mode. Add that to the hardware hacks. Grafting the PCjr monitor connector onto a good CGA monitor, or building an adaptor to connect a standard CGA monitor. ISTR at least one such adaptor was sold by a 3rd party vendor.


 * First of all, please sign your edits so people can follow threads and see who said what. Secondly, the monitor comments seem bogus -- it was the same quality as the 5153 (I have both). There is no significant difference in 80-column mode between both monitors, so I'm not sure what you're getting at. --Trixter 15:31, 29 November 2006 (UTC)

Internal modem -proposed changes
Hello,

I've never edited any Wikipedia entries before, so I'm going to lay out in here some info, and hopefully get some guidance from some of you on how to determine if it's relevant, what info I need to back up these claims, and where in the article it might go.

The internal modem that was sold by IBM was actually made by Novation, the maker of the famous Apple Cat. There is a proprietary command set to command the modem. This is stated in the article, but I think it's important to state that it's made by Novation. Also, I think there might be a better way to contrast this to the Hayes compatability than how it's written right now. Check out the Novation CAT article.

This modem is a 300 baud modem. I'm going to try to find some more documentation that states exactly which modes it will do, as well as other baud rates. I think it does 110 and 150.

A feature of this modem that is one of the 'raves' of Novation's modems is it's call progress detection and reporting. It will not just tell you if a line is busy, but also tell you when the line is ringing (with one 'ringing' response per ringback tone), and when there is human speech on the other line.

And with the Cartridge BASIC there is a basic command TERM that will load a terminal emulator written in basic. This terminal emulator is written to work with the proprietary command set only.

Maybe the Novation CAT page should have a blurb about this modem too?

Rixoff 05:36, 25 August 2007 (UTC)

Ding dong, the trivia is dead...
I re-wrote the article (sort of), in order to incorporate most of the pertinent information from the trivia section. As I said in my edit summary, I left a few items out, either due to being too trivial (books being written) or incoherant ("The PCjr was manufactured in Lewisburg, Tennessee by Teledyne. Roughly 500,000 units were shipped." - When? Was this the only manufacturing location? If not, 500,000 units shipped in total, or 500,000 shipped from Lewisburg?). Give the new version the once-over, and let me know what you think! --Badger Drink 06:16, 1 September 2007 (UTC)

PCjx pictures
http://www.alphalink.net.au/~sedmonds/computers/ The PCjx needs its own article. From those images one can see that it was a completely different machine from the PCjr. The power supply is all internal, in a metal box, and uses a standard IEC cord. The ports on the back are completely different from the PCjr and it has a cooling fan as well as two metal shielded 720K floppy drives. Oddly, it does not appear to have any provision for "sidecar" expansion modules like the PCjr. The case is also mostly metal, unlike the PCjr's all plastic case. Unfortunately there's no shot of the right side that shows what the black lump is. It looks like the only things common between the two are their size, CPU and the two cartridge ports.

Keyboard and serial DMA?
The PCjr also lacked a DMA controller. Thus, the 8088 CPU had to service standard system interrupts such as the serial port or the keyboard directly. Hence, the PCjr couldn't be used with modems faster than 2400 baud, and it would refuse to process keyboard input if its buffer was full.

This paragraph is suspect. On the PC, neither the keyboard nor serial port are DMA driven or buffered in hardware and must be serviced by interrupts on a byte basis. FIFOs were not added to the serial port hardware until the introduction of the 16550 UART. Also, any computer will refuse to process keyboard input once its buffer is full!

What I suspect was meant was that keyboard or serial data could be lost during a floppy drive transfer, since DMA was used on the PC to service the FDC, and the lack of a DMA controller on the PCjr presumably meant that either interrupts had to be disabled or the CPU could not service other interrupts quickly enough. 24.4.198.162 (talk) 21:30, 17 October 2009 (UTC)

Press-release journalism?
Why does the article keep switching to present tense? My guess is that a lot of the text was copied and pasted from another, very old, source. The style of the article even changes in these sections.--RJBowman (talk) 06:11, 17 February 2015 (UTC)


 * No text has been copied from elsewhere as far as I know; certainly not within my own edits. Present tense is used when appropriate as per WP:COMPNOW. Ylee (talk) 06:14, 17 February 2015 (UTC)

Lead
For this to have any shot at GAN, the lead must be expanded to properly summarize the article. This is hard, but the lead is the most important part of the article. Hekerui (talk) 09:18, 20 July 2015 (UTC)

Did you rewrite the lead? Does this still need to be done? — Bptdude

History - not fully PC compatible - Microsoft Flight Simulator
In this section it states,

"In practice the PCjr proved incompatible with about 60% of PC applications including WordStar and two programs often used to test PC compatibles' compatibility, 1-2-3 and Microsoft Flight Simulator"

None of the references cited indicate that the PCjr was incompatible with Microsoft Flight Simulator. The PCjr was in fact compatible with Microsoft Flight Simulator 1.0. I played it all the time. — Preceding unsigned comment added by 167.220.151.252 (talk) 18:53, 3 December 2015 (UTC)

RF modulator
In the section, "Differences from the IBM PC", it is claimed that the PCjr has a "built-in RF modulator". As I recall you need an external TV adapter to feed the video monitor signal into the antenna connection of a TV. Does this need to be corrected? — Preceding unsigned comment added by Mcsew2k (talk • contribs) 17:24, 23 September 2018 (UTC)

Wiki Education assignment: First Year English Composition 1001
— Assignment last updated by WKJacob (talk) 14:06, 24 August 2023 (UTC)