Talk:Floppy-disk controller

Confusing
This is a confusing article. The introduction speaks of FDCs in general, but the article launches into a detailed description of a particular FDC - which the article does not identify - and also a particular FDC IC, which again the article does not identify. Mirror Vax 07:34, 3 January 2006 (UTC)

Not So Confusing
The vast majority of FDCs are compatible from a coding perspective, they use the same ports for the same purposes (and provide the same problems). For those interested, more in-depth information is located here. Kemp 09:14, 7 April 2006 (UTC)
 * OSfaq have moved, now at here, but are in migration from phpWiki to MediaWiki; if in a future not work, check this. --Museo8bits 11:36, 23 September 2007 (UTC)

In addition, there is a more complete guide than the one in "external links" here. It has the commands description, which is omited here. -- Mr. X, sometime, somewere.

Or is it?
I have to disagree. While the NEC uPD765 floppy disk controller and it's clones (Super I/O, etc.) are the standard for IBM PCs, the Western Digital WD179X chipset was used in many types non-PC home computers in earlier years. Also the custom FDCs found in the Amiga and Apple / Macintosh computers deserve mention, especially due to their design and innovation at the time.

If the article was made more general, and then listed specific data on the other types of FDCs I've mentioned, it would be possible to then add useful information about the history of their development (from multi-chip designs spanning two or more PCBs to single IC devices) and how many of them work with an external VCO as well as the CPU-controlled FDC. Alone, the origins of the IBM PC-specific FDC and implementation details are rather dull. ;) —Preceding unsigned comment added by 69.110.2.237 (talk • contribs) 18:45, 29 June 2006


 * A more general article is quite appropriate. Feel free to extend it. -R. S. Shaw 21:12, 29 June 2006 (UTC)

Floppy controllers today
I think that there's something missing in this article: The article doesn't mention what floppy controllers look like in 2014. I mean, in the beginning, there were ISA floppy controllers which were later followed by on-board floppy controllers. Today, floppy controllers have started to disappear from MBs which makes it difficult to use floppy drives if you really need to. I happen to have a floppy drive in my computer but it doesn't work because I can't connect the drive to the MB because the MB has neither an on-board floppy controller nor is there a floppy connector to connect the floppy wire to. Fortunately, I don't need the drive. But if I really needed to use it - what would I do? Buy a PCIe floppy controller? (That is, do PCIe floppy controller exist at all?) -- 2001:A60:21A5:7801:213:3BFF:FE04:1EE (talk) 01:36, 10 February 2014 (UTC)


 * You buy a small computer like RPi that is capable of making measurements of 500 kbit/s pulses and connect it to the read output from the floppy. The computer needs to measure the time between the pulses with a precision of at least 0.6 µs. The rest is a software processing business. Bytesock (talk) 00:10, 24 April 2016 (UTC)

"1.44 MB"
So, "1.44 MB" is/was used everywhere – but it's nonsense. 2880 sectors make exactly 1474560 bytes capacity, equivalent to 1.47456 MB (M=10002) or 1.40625 MiB (Mi=10242). "1.44 MB" were created when people mixed binary 1440 KiB (Ki=1024) with decimal M=1000K, so it's actually 1.44 × 1000 × 1024 bytes which is neither decimal M nor binary Mi. Can we please just use K or Ki for 1024 without reiterating this nonsense? --Zac67 (talk) 20:24, 23 April 2016 (UTC)


 * In almost all markings on brochures, hardware, software etc. The 3.5 inch "HD" drive was labeled "1.44MB" regardless of the mathematical truth. The recognition and name comparison factor for people that stumble on these devices should not be underestimated. KB has always been an abnormality because the "K" factor doesn't exist and become inconsequential for M and higher prefixes. Whenever storage size has been discussed for computers, base 2 has been implied. Harddisk manufacturers were the ones that started to confuse people by using base 10 to inflate their numbers. Thus to be consistent, base 2 is used even if the SI system is based on base 10 and not let self interest marketing department confuse the units. A similar story can be found with "DB-9" connectors that actually don't exist. The correct name is "DE-9", DB-9 is missnominer. Bytesock (talk) 21:44, 23 April 2016 (UTC)


 * Does it mean WP:MOS, WP:COMPUNITS and such do not apply when something is common practice? I'd be fine using KiB btw – using k for 1024 is pretty strange because the world doesn't even do that. In storage, binary prefixes are not used conherently – they are only used in software; datasheets and hardware documentation use decimal prefixes. --Zac67 (talk) 21:57, 23 April 2016 (UTC)


 * WP:COMPUNITS etc may not have taken into account all the fractional decimals and the confusion that causes when you actually starts to make calculations on encoding, bytes, sectors, tracks, discs, filesystems etc. Not too rarely there's a need to get it right to the bit to be sure the fractions are not because one missed to take encoding into account etc. This comes into play when trying to rescue old floppies. One can put a footnote k=1024, or use units of 160 * 2^10 bytes etc. Bytesock (talk) 00:02, 24 April 2016 (UTC)


 * Took a look around: List of floppy disk formats has an extra column Marketed capacity and a footnote on this issue. Would you agree to moving the "1.44 MB" to the comment column? --Zac67 (talk) 19:10, 25 April 2016 (UTC)


 * Make an extra column between Format and Capacity to indicate "marketed" format. One thing to keep in mind is that many IBM drives had "1.44" inscribed into the eject button. So anyone that hasn't ever used these devices would most likely more easily orient themselves with a such hint. Btw there's data missing like rpm for the 160 kB format and others, if you can find those, it would be a good thing. The point with these tables is that they are useful when rescuing data from floppies before the bit-rot and to get a grasp of what possibilities that were available at the time. Bytesock (talk) 22:23, 25 April 2016 (UTC)

External links modified
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Format Data Section inaccuracies
In the "Format Data" section, there are references to SD and DD as in "Single Density" and "Double Density".

The C64 1541 is Single SIDED, not Single DENSITY.

I have changed SD to SSDD (as in Single Sided, Double Density).

Other "SD" entries may be incorrect too. Please check.

If you think I am incorrect, please let me know.

Chris Fletcher (talk) 08:24, 26 November 2019 (UTC)

Apple vs IBM FD interfaces.
AFAIK Apple had Shugart Associates remove most of the electronics from the drive they purchased and included Apple's own version on their controller card so that the drive interface looked nothing like the figure in this article. The Apple FD interface for example directly accessed the stepper motor as opposed to the step and direction conventional interface. Likewise, Apple implemented GCR in the controller as opposed to FM/MFM in conventional FD. IBM on the other hand bought a "stock" FD for the PC with the drive interface corresponding to the figure in this article. I suppose I could dig up some RS's if anyone can dispute this but to me it is blue sky :-) Tom94022 (talk) 21:50, 6 December 2021 (UTC)

Merge Shugart Bus article into this article
The term "Shugart bus" appears to be a term-of-art invented in Wikipedia since most of the Google search hits appear circular and there are no hits in Google News nor patents. The term is also a part of any Shugart drive interface which includes the data interface and the power interface. The discussion in the Shugart bus article is limited to two specific Shugart floppy disk drives models that became industry standard FD interfaces. Accordingly I propose merging the Shugart bus article into this article and then add linkages to this article in the 8-in & 5¼-in Section of the FD article. Tom94022 (talk) 20:07, 18 December 2021 (UTC)
 * Support subject is dubious and the source article is small. ~Kvng (talk) 18:22, 22 December 2021 (UTC)
 * Keep separate. Back in the day, the term was quite commonly used referring to the 8" and 5.25" diskette drive interfaces. While Shugart bus is a stub only at present, there is enough to tell about the topic that it could (and should) become a full-blown article in the future. Merging the topics makes it more difficult to incrementally grow the contents. --Matthiaspaul (talk) 04:24, 25 December 2021 (UTC)
 * AFAIK back in the day the term was Shugart interface or some variant, e.g. SA800 interface. I did a quick search on "Shugart bus" with no hits back in the day - one reference cited in this article is from 2011 (German?) and uses the term but the reference is otherwise inaccurate so it is not an RS.  The other reference does not use the term.  If you have any RS's for the use of the term I would appreciate them.  Regardless, incorporating the stub into the does not preclude incremental growth within this article.  Tom94022 (talk) 19:09, 25 December 2021 (UTC)
 * Hi Tom, a quick Google search revealed several sources mentioning "Shugart bus" or "Shugart-Bus", sometimes with a number of signals added, but I too found some of those references to be inaccurate in some way, hence I didn't list them here as RS. However, I've also used the term myself back then, so it does not come as a surprise to me that the article is named this way. I guess, however, it was an informal name, so there might be a better more formal name we might switch to. I might be able to check some old magazine articles but they are stored away and inaccessible at present, so that might need have to wait some while.
 * I did a Google books search from 1975 to 1990 first on "Shugart bus" and then on "Shugart interface" - there was one reliable hit (10 hits total) on the former but many on the latter. I did find one German patent hit on "Shugart bus." I also searched my local files which includes a lot of scanned material from that era with zero hits. This supports my recollections from that time period that the term of the art in English was not "Shugart bus" but more along the lines of Shugart interface or some variant such as SA800 interface compatible, etc.  Tom94022 (talk) 20:29, 27 December 2021 (UTC)
 * Regarding merging, in my experience merging often more or less stops further development on topics (and thereby also splitting out stuff into new articles at a later stage). No problem if there is nothing that could be reasonably said about a topic, but in this case I would like to see actual pinouts and a description of the signals (properly sourced, of course - there definitely were publications covering this in detail back then), which, however, would be too much in the floppy disk controller article. Since the Shugart bus has (well, just) enough sources to survive standalone I'd perfer to keep it that way and see more (better) sources and contents added over time, of course. --Matthiaspaul (talk) 19:45, 25 December 2021 (UTC)
 * On the other hand, I personally am no willing to work on the Shugart bus article but would be willing to start into this article along with linking from the Floppy disk article where there is some drive discussion. So a bird in the hand might be worth something :-) Tom94022 (talk) 20:29, 27 December 2021 (UTC)


 * Keep separate for now. has added a couple of (low quality but noncircular) refs that seem to address 's concerns. ~Kvng (talk) 16:17, 27 December 2021 (UTC)
 * I looked at the two refs before making the recommendation, they were added in 2019 and predate 's recent edit. The first ref does not use the term "Shugart bus" and the second ref is from 2011 long after the relevant time (German too?) and has other errors so I suggest it is not an RS.  There really are no relevant RS's so far.  Again, I would like to point out that the Shugart bus lede is incorrect, the bus is only a part of the interface.  Each entire defacto interface is the proper subset of the Floppy disk controller article and belongs here.  BTW there were three defacto standard FD interfaces, one each for 8-inch, 5¼-inch and 3½-inch, only the first two were initially Shugart drive interfaces.  Please support the move.  19:38, 27 December 2021 (UTC)
 * what's the downside to fixing the problems with Shugart bus and leaving the articles separate? Do you still believe this term was invented by Wikipedia? ~Kvng (talk) 15:42, 28 December 2021 (UTC)
 * I think it would wind up duplicating what is already in this article which offends me since it then becomes an opportunity for inconsistancies. I suspect the term may have been more common in non-US English speakers (German for sure) and since I can't find any contemporaneous usage IMO dedicating an article to the term is WP:undue and/or not notable.  Tom94022 (talk) 21:20, 28 December 2021 (UTC)
 * I agree duplication is bad. I think it would be difficult to make a notability case for this because we'd have to resort to offline sources. I'm no longer opposed to the proposed merge. ~Kvng (talk) 15:17, 31 December 2021 (UTC)
 * I have thought about this for a couple of days and have searched a bit more for references. While I haven't checked my personal archive of magazines (for the reasons stated above), I have found the term "[standard] Shugart bus" being mentioned in a number of old magazines which can be found online. I also found variations like "[Shugart] floppy bus", "[Shugart] floppy interface", "Shugart connector", "34-pin mini-floppy bus", etc. Most of the sources are German, but I also found a few English ones.
 * So, my memory served me well when I remembered that I used the term myself back then. From the sources found so far it is out of question that it was used by others as well. Notability is established as well (and a function of coverage, not of the usage of a particular term in a particular language, anyway).
 * If another term was more common in the English speaking world, I propose to rename the article, perhaps "Shugart floppy bus" to avoid any possible confusion with SASI? However, "Shugart bus" is not wrong as well.
 * Regarding merging it into the "floppy disk controller" article, I think that article should discuss floppy disk controllers in general (it already does, but could list more examples). However, when it discusses specific bits and signals this is IMO too specific for a generic floppy disk controller article. So, perhaps this information (which I still find valuable) should be moved into articles about specific floppy controller/interface families, and if we'd have one such article centered around Shugart-related stuff, a detailed description of the bus interface (and some common variations) might be appropriate there - if so, "Shugart bus" and its variations could be changed into redirects to such article. However, redirecting it to "Floppy disk controller" would be a too generic target to discuss the topic at the desired detail level.
 * --Matthiaspaul (talk) 17:13, 1 January 2022 (UTC)
 * Matthiaspaul is a native German speaker and his research showing that "Most of the sources are German, but I also found a few English ones" leads me to conclude that the term is not appropriate as an article title in this English language Wiki ; I would appreciate any English language references so that all interested editors can make their own assessments as to both as to notability and appropriateness.
 * As far as i can tell not one of the references added by Matthiaspaul that are in English use the term "Shugart bus". Tom94022 (talk) 20:26, 1 January 2022 (UTC)
 * "Shugart floppy disk drive interfaces" is the appropriate title for the "Shugart bus" article but this article already has a section called "Interface to the floppy disk drive" that covers the standard 3½-inch FDD interface which thru the MIC committee is arguably a Shugart instigated FDD interface. What I am proposing is essentially to create three subsections in this article, one for each of the three "standard" interfaces.  I think this makes more sense than having two of the three interfaces in a separate article with an uninformative title.  I may be quicker for me to go ahead and add to this article which will make the Shugart bus article redundant and thus end this dialog.
 * --Tom94022 (talk) 19:58, 1 January 2022 (UTC)
 * --Tom94022 (talk) 19:58, 1 January 2022 (UTC)

I suppose we could re-title the Shugart bus article as Floppy disk drive interfaces, move the one section from this article and insert appropriate links into this article and the Floppy disk article. Shugart bus would then become a redirect. Tom94022 (talk) 20:47, 1 January 2022 (UTC)
 * Sounds good to me, I have therefore renamed the article into "Floppy disk drive interface" (I used the singular form per MOS even if we will discuss multiple busses/interfaces in there). --Matthiaspaul (talk) 19:31, 2 January 2022 (UTC)
 * You really should not have gone ahead without consensus - Personally I think it belongs in this article, but I started over there and we can always move it here if that turns out to be preferred. Before moving the 3.5-inch interface material from this article into "Floppy disk drive interface" and further restructuring this article I would like to hear from at least Kvng Tom94022 (talk) 21:56, 2 January 2022 (UTC)
 * Oh, sorry, I must have misunderstood you - this was basically meant as a nice gesture to you as you seemed to be tired of the discussion and in a bit of a hurry to start writing. From the discussion and your suggestion above I assumed we would have reached consensus and found a good compromise addressing most of our both concerns (that is, not using the "Shugart bus" title for the article, but also not having all the to-be-expected floppy bus / interface stuff in the floppy controller article, and by moving the bus / interface related stuff into the renamed article also avoid redundancy except for some minor "glue"), and that we even would have found a nice descriptive title "floppy disk drive interface" which makes sense in a series of articles about floppy related topics and is generic enough to potentially not only discuss the Shugart bus / interface but also a few others (IMO that's even better than having a dedicated article on the Shugart bus only). Let's see if Kvng prefers a different arrangement... --Matthiaspaul (talk) 23:21, 2 January 2022 (UTC)

Merge Floppy disk drive interface article into this article

 * If this is now going to be an article about floppy interfaces of all kinds, I have a weak opinion that it would be best for readers if we merged the content into Floppy-disk controller. These are both fairly esoteric topics that are not appropriate to merge into Floppy disk but, do they each need their own stand-alone article? Probably not. ~Kvng (talk) 01:39, 3 January 2022 (UTC)
 * I agree with merging Floppy disk drive interface into Floppy-disk controller. The "interface" page has barely four paragraphs worth of core content, and the giant tables at the end could be collapsed. It's mostly IBM PC related anyway, so incorporating it into this article could encourage folks to come forward and add some non-IBM info too. DraugTheWhopper (talk) 17:02, 5 November 2022 (UTC)

I have a weak opinion that adding 600 words to this 1600 word article would be bad for the reader. Note that the article really is about FD interfaces; they were pretty much standard; IBM was for a while just the biggest user and IBM set no FD standards beyond the 8-inch media and format. Tom94022 (talk)

New list of FDD Controllers
The list posted is a collection of undue and/or unsupported FDDCs. In many cases it simply lists a computer which had a FDDC of one form or another without identifying the FDDC explicitly. It ignores the vast history of FDDCs starting with the first one, the FDDC internal to the IBM 2835 and a whole raft of others. Accordingly I have deleted the whole list as not encyclopedic. A list of significant FDDCs with references would be appropriate but it appears to me that this newly added list fails to meet that requirement. Tom94022 (talk) 18:09, 15 July 2022 (UTC)


 * the idea is to add a system to the list if you know about it.
 * or let other people add to the list.
 * why is the list when complete not encyclopedic? 158.181.83.72 (talk) 18:23, 15 July 2022 (UTC)


 * This proposed list is not encyclopedic as it stands because it consists mostly of unreferenced items (e.g. woz machine), links not supporting inclusion (e.g. A_5120) and/or WP:UNDUEinsignificant FDDCs (e.g. FDDC in PC_1715) not worthy of inclusion in Wikipedia. A list of all FDDCs could be a very large standalone article but it would be hard to generate without violating WP:STANDALONE especially WP:OR.  Also note that very quickly FDDCs were offered on combination pcbs, for example with serial/parallel ports or with HDDCs.  As I said, A list of significant FDDCs with references would be appropriate...  Such a short list might include significant examples supporting the text of the article such as:
 * The FDDC in the IBM 2835 - the first one used by IBM for control store load
 * The FDDC in the IBM 3740 - IBM's first one for other than control store load
 * An early pcb FDDC from a system house, e.g. DEC
 * An early pcb FDDC not from a system manufacturer, possible one for a DEC machine
 * An early combination pcb/
 * The woz machine pcb
 * The IBM PC FDDC, a pcb using the NEC uPD765 or equivalent controller IC.

controller.
 * The first or an early chip set
 * The first or an early chip
 * The first integration into a host chip set
 * As you can see only one or mayve two of the current list makes such a list consistent with Wikipedia guidelines. Tom94022 (talk) 00:02, 17 July 2022 (UTC)

IBM manuals as reference
i know a bit about computers, but i couldn't even start making sense of these sources in 5 minutes.

they have no table of content, they start with endless numbers of pages of weird diagnostics error messages.

they require a weekend's worth of special training in IBM idiosyncrasies even for an educated person.

add some minimal amount of context, like page numbers. or better yet, find a human readable document on this controller.

with a reference like this you can claim almost anything. Nowakki (talk) 06:09, 20 September 2022 (UTC)
 * Actually there is a table of content on page 1 and then at the beginning of each section. The specific pages relied upon are listed in the reference. While you may not understand IBM MLM's, there are many who do and can validate or correct the statement in this article regarding the information on those pages.  Tom94022 (talk) 18:03, 20 September 2022 (UTC)

Integrated FDD?
The recent addition of a paragraph on an Integrated FDD is in my experience dubious in general I know of no such drive. Perhaps, the editor is thinking of USB FDDs which indeed do consist of an FDD with an industry standard interface and a bridge controller (FDD interface <-> USB) in which case the paragraph should be rewritten to make the distinction clear, there is no integration. Tom94022 (talk) 18:24, 20 September 2022 (UTC)


 * Commodore 1540
 * drive + controller in one unit. Nowakki (talk) 21:29, 20 September 2022 (UTC)
 * The cited article says, The 1540 is an "intelligent peripheral" in that it has its own MOS Technology 6502 CPU (just like its VIC-20 host) and the resident Commodore DOS on board in ROM ... The 1540 is relatively rare.. And "intelligent peripheral" is not really an FD is it?  Inside is an industry standard FD with a bridge controller, not the asserted "integrated parts" in the conventional sense, just packaged in the same box.  Nor is this "rare" unit supportive of the asserted "case of many home computers."  Basing the added paragraph on the Commodore 1540 is WP:Undue.  Tom94022 (talk) 22:05, 20 September 2022 (UTC)
 * same is true for any of the devices listed in the commodore infobox at the bottom of the page.
 * they all contain the drive and the controller. at least for all the PET models i am sure that they have 2 PCBs and a connector that is basically the same as the 34-pin connector. Nowakki (talk) 22:19, 20 September 2022 (UTC)
 * Since we both agree that all these Commodore devices contain a controller and a standard drive then I think we agree that the paragraph is incorrect when it asserts "integrated parts." Actually the internal controller to drive connector depends upon the form factor doesn't it - from the Commodore 8060: The drives in the 806x series are full-height Shugart SA-800s. and therefore inside the box is an 8-inch FD with its connector and standard interface. Again, not integrated in the common sense of the term.  Furthermore, the external interfaces from these boxes are not floppy disk drive interfaces in any sense, as the list info box states the Commodore interfaces are either Parallel IEEE for 8-inch or Serial CBM for 5¼-inch - not in any sense an FDD interface.  It seems to me that all of what you have cited confirms the paragraph as currently written is dubious.  I think the most u can say and support with references is that there are intelligent floppy disk drives like the Commodore series and USB Floppies that contain a controller within that then has an interface to an industry standard FD. AFAIK, no one ever integrated an FDD controller into an FDD the way SCSI and IDE were integrated into an HDD, in the latter case the low-level HD interface disappeared. Tom94022 (talk) 00:19, 21 September 2022 (UTC)
 * i have changed the wording Nowakki (talk) 01:46, 21 September 2022 (UTC)
 * Your change doesn't correct anything, so I will try my version. Tom94022 (talk) 05:47, 21 September 2022 (UTC)