berger@clio.las.uiuc.edu (09/21/88)
The ST-251 has 820 cylinders, 4 heads, and 17 sectors per track.
It has a 40 ms access time with a 3-200 microsecond step pulse
rate.
Mike Berger
Department of Statistics
Science, Technology, and Society
University of Illinois
berger@clio.las.uiuc.edu
{ihnp4 | convex | pur-ee}!uiucuxc!clio!bergerrjs@moss.ATT.COM (09/21/88)
In article <16800373@clio> berger@clio.las.uiuc.edu writes: > >The ST-251 has 820 cylinders, 4 heads, and 17 sectors per track. >It has a 40 ms access time with a 3-200 microsecond step pulse >rate. > > Mike Berger > Department of Statistics > Science, Technology, and Society > University of Illinois A quick calculation will show that the above information cannot be correct. 4*820*17*512(sector size)=28,549,120 bytes, a bit short of the advertized 40M. The ST-251 definintely has 6 heads and 17 sectors/track. The number 815 sticks in my mind as the number of cylinders, but 820 may well be correct. (Actually, the 17 sectors/track is a property of the formatting program, but is the value to use if you want the rated capacity). Robert Snyder {att|ihnp4|clyde}!moss!rjs (201) 386-4467 The above statements are my own thoughts and observations and are not intended to represent my employer's position on the subject(s).
dougm@venus.SanDiego.NCR.COM (Doug Marshall) (09/21/88)
In article <16800373@clio> berger@clio.las.uiuc.edu writes: > >The ST-251 has 820 cylinders, 4 heads, and 17 sectors per track. ~~~~~~~~ My book shows that it has 6 heads. --- Doug Marshall <Doug.Marshall@SanDiego.NCR.COM> +1 619 485 3494 <...!ncr-sd!venus!dougm> FAX 485-3788
woodman@suvax1.UUCP (David Woodman) (09/26/88)
> In article <16800373@clio> berger@clio.las.uiuc.edu writes: >> >>The ST-251 has 820 cylinders, 4 heads, and 17 sectors per track. > ~~~~~~~~ > My book shows that it has 6 heads. And the ST-251 only has 17 sectors per track IF formatted by an MFM controller. It will have 26 sectors per track if formatted by an RLL controller. I know, I know, the ST-251 is spec'd as an MFM drive but a friend of mine is running it on an RLL controller. I don't advocate it, but it seems to work. (P.S. The ST-251 seems to come in two flavors, 40ms & 28ms. When I bought mine, it turned out to be 28ms but was charged for the 40ms. Either the company did not know the difference or there is something I don't know about.) ------------------------------------------------------------------------------ David Woodman UUCP: ...!uw-entropy!dataio!suvax1!woodman Seattle University USNail: P.O. Box 23202, Seattle WA 98102 Phone: (206) 223-9470 ------------------------------------------------------------------------------
sarathy@gpu.utcs.toronto.edu (Rajiv Sarathy) (09/26/88)
> ... > > (P.S. The ST-251 seems to come in two flavors, 40ms & 28ms. When I > bought mine, it turned out to be 28ms but was charged for the 40ms. > Either the company did not know the difference or there is something > I don't know about.) > >------------------------------------------------------------------------------ > David Woodman UUCP: ...!uw-entropy!dataio!suvax1!woodman The ST-251 is a 39ms drive. The ST-251-1 is a 28 ms drive. How many people have used RLL encoding on their ST-251? A vendor here advised me not to, saying the hard drive would probably die on me within 6 months. He suggested buying an ST-251-R, which he said is better suited to RLL. Any opinions? Please e-mail to sarathy@gpu.utcs.utoronto.ca If that doesn't work (it's a new address) then try sarathy@gpu.utcs.toronto.edu Using 'R'eply from rn will probably not work due to the UUCP addition to the Reply-To field, above. Thanks, --Raj ----- Disclaimer: I'm just an undergrad. -----