sbw@naucse.UUCP (Steve Wampler) (11/09/88)
I have a (he thinks) fairly simple question about replacing
the drive in a 3B1. I see that Miniscribe has a drive, the
model 6128, that is ST506/412, 110.1MB(formatted), with 1024
cylinders and 8 heads. Can I drop one of these straight into
my 3B1 (which currently has a 40MB drive)? If so, where are
some good places to get the above drive at a discount? Are
their any competitor drives with similar/better features?
Another thing I'm considering is to drop in two MiniScribe
3085 (1/2 height) drives in place of the my current full-height
drive (slightly more storage than one 6128, but better avg
access time). However, from John's hardware notes, this sounds
like considerably more work - not to mention the problem of
tying them both down inside the case. Any comments?
--
Steve Wampler
{....!arizona!naucse!sbw}kevin@kosman.UUCP (Kevin O'Gorman) (11/12/88)
In article <1015@naucse.UUCP> sbw@naucse.UUCP (Steve Wampler) writes: >I have a (he thinks) fairly simple question about replacing >the drive in a 3B1. I see that Miniscribe has a drive, the >model 6128, that is ST506/412, 110.1MB(formatted), with 1024 >cylinders and 8 heads. Can I drop one of these straight into >my 3B1 (which currently has a 40MB drive)? > ... > Any comments? Hmmmm. The standard "67MB" UNIX PC drive has 1024 cylinders, and 8 heads. It is actually a 71.3 MB drive, but after allowing for alternate sectors there are 67 MB available. How does the 6128 get 110.1 MB??? If it had 25 sectors per track it would be smaller than that; if it had 26 sectors it would be larger. I could probably work it out, but the idea is clear: any drive with more than 67 MB available has more than 17 sectors, or requires a hardware modification to the UNIX PC. I don't know if the drivers can deal with more than 17 sectors per track. Just about all drives I have seen stick to exactly this number.
jbm@uncle.UUCP (John B. Milton) (11/12/88)
In article <1015@naucse.UUCP> sbw@naucse.UUCP (Steve Wampler) writes: [one big drive] >Another thing I'm considering is to drop in two MiniScribe >3085 (1/2 height) drives in place of the my current full-height >drive (slightly more storage than one 6128, but better avg >access time). However, from John's hardware notes, this sounds >like considerably more work - not to mention the problem of >tying them both down inside the case. Any comments? My current thinking on my hard drive upgrade: A small square board bolted to the fan grate on the back left. All those 3b1s out there are proving you don't need the left fan. In the 7300s its ok, but in the 3b1 is produces dead spots in the air flow and two fans actually makes it worse. My idea is to just let the connectors stick out the grate. There will be 6 connectors: 1 hard drive 34 pin, 4 hard drive 20 pin connectors and one 34 pin floppy tape connector. There are four hard drive connectors so that you can take the internal drive out of the machine to reduce the load on the power supply. As I have mentioned before in other postings, the system software already supports two hard drives. I intend to re-write the gd driver to be able access two more hard drives, one floppy tape drive and maybe one more floppy drive (AT high density). Convergent had a lot of trouble with this last one, but I've seen it done before, so I think it's possible. BTW, does anyone have specs or practical experience with ST-506 hard drive data cables (the 20 pin one) as far as maximum length goes? John -- John Bly Milton IV, jbm@uncle.UUCP, n8emr!uncle!jbm@osu-cis.cis.ohio-state.edu (614) h:294-4823, w:764-4272; MS-DOS is a beautiful flower that smells bad!
lenny@icus.islp.ny.us (Lenny Tropiano) (11/13/88)
In article <498@kosman.UUCP> kevin@kosman.UUCP (Root) writes: |>In article <1015@naucse.UUCP> sbw@naucse.UUCP (Steve Wampler) writes: |>>I have a (he thinks) fairly simple question about replacing |>>the drive in a 3B1. I see that Miniscribe has a drive, the |>>model 6128, that is ST506/412, 110.1MB(formatted), with 1024 |>>cylinders and 8 heads. Can I drop one of these straight into |>>my 3B1 (which currently has a 40MB drive)? |>> ... |>> Any comments? |> |>Hmmmm. The standard "67MB" UNIX PC drive has 1024 cylinders, and 8 heads. |>It is actually a 71.3 MB drive, but after allowing for alternate sectors |>there are 67 MB available. How does the 6128 get 110.1 MB??? ... The Miniscribe 6128 is a 128MB (unformatted) and 109MB (formatted) HD with 8 heads and 1024 cylinders. The only bad part is that it uses the RLL recording format, something the WD1010 disk controller doesn't support. What you have in your machine with a 85.3MB (unformatted) and 71.3MB (formatted) Miniscribe 6085 drive that uses the MFM recording method. If you want >1024 cylinders the WD2010 needs to be used. If you need >8 heads then you need the P5.1 upgrade to be installed. -Lenny -- Lenny Tropiano ICUS Software Systems [w] +1 (516) 582-5525 lenny@icus.islp.ny.us Telex; 154232428 ICUS [h] +1 (516) 968-8576 {talcott,decuac,boulder,hombre,pacbell,sbcs}!icus!lenny attmail!icus!lenny ICUS Software Systems -- PO Box 1; Islip Terrace, NY 11752
thad@cup.portal.com (Thad P Floryan) (11/14/88)
Re: John Milton's question how far the 20-wire data cable can be extended ... I've seen runs up to 16 feet (the spec permits 20 feet), but those were NOT on a UNIC-PC. Considering all the care with which the UNIX-PC has been shielded, it's not clear WHAT would happen if "bare" ribbon cable were to be brought out that far from the system (esp. in a room with flourescent lamps and other EMI/RFI garbage). Thad Floryan [thad@cup.portal.com (OR) ...!sun!portal!cup.portal.com!thad]
clewis@ecicrl.UUCP (Chris Lewis) (11/14/88)
In article <1015@naucse.UUCP> sbw@naucse.UUCP (Steve Wampler) writes: >I have a (he thinks) fairly simple question about replacing >the drive in a 3B1. I see that Miniscribe has a drive, the >model 6128, that is ST506/412, 110.1MB(formatted), with 1024 >cylinders and 8 heads. Can I drop one of these straight into >my 3B1 (which currently has a 40MB drive)? The Miniscribe obviously has to have more than 17 sectors per track which isn't exactly standard ST506. You'd probably be better off trying a Maxtor XT1140 (15 heads, 920 cylinders) which formats to slightly over 120 Mb. That is of course if a 3b1 supports an additional head select line (which the original ST506 didn't have). Many of the BYTE advertisers list them. (BTW: XT1140 is 28 ms. avg access) -- Chris Lewis Ferret Mailing list:{uunet!attcan,yunexus,utzoo}!lsuc!gate!eci386!ferret-request {uunet!attcan,uunet,utgpu,yunexus,utzoo}!lsuc!ecicrl!clewis (or lsuc!gate!eci386!clewis or lsuc!clewis)