Talk:Tallgrass Technologies

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Patented all-digial data separator was not used for hard disk
The patented all-digital PLL data separator described in the article was not used for hard disk drives, even though it was invented by the founder of Tallgrass. The all-digital PLL was not suitable for the 5 Mbps pulse rate from an ST-506 hard disk, so a conventional analog PLL based data separator was used.

Per the patent, the data separator needs to be clocked at 32x the pulse rate, and the patent gives an example of 16 MHz for a standard-density 5 1/4-inch floppy (250 kbps pulse rate). For an ST-506 hard drive, this would have required the data separator to run at 160 MHz, which was well beyond the technology at the time. The fastest bipolar PROMs available at that time which could have been employed in such a data separator had an access time (and cycle time) of around 35ns, which gives an upper bound of 28.5 MHz for a PROM-based data separator.

I saw the Tallgrass controller board may times in the early 1980s, but there do not appear to be any photographs of it on the internet, and only a few photographs of the PC host interface board. --Brouhaha (talk) 16:46, 10 November 2021 (UTC)

Claim of being "first" hard disk for IBM PC is questionable
Tallgrass was fairly early, but the claim that the Tallgrass hard disk system for the PC was the first such drive is almost certainly wrong. By the first quarter of 1982, there were many hard disk systems available from many vendors, including Datamac, Davong, Santa Clara Systems, Inc., Tecmar, and VR Data. By the second quarter, more companies offered them, including ASAP Computer Products, Control Systems, Corvus, (PC)2, Professional Micro Systems, and QCS. --Brouhaha (talk) 18:05, 10 November 2021 (UTC)


 * Tallgrass released their hard disk products in late (probably November) 1981. It was a close race, but Tallgrass, it seems, was the first. I found some more citations to back that claim up. DigitalIceAge (talk) 21:47, 21 March 2023 (UTC)