MALCOLM@tower-vax.city-poly.ac.UK (05/02/90)
I have an Atari Megafile hard drive which I want to use with a non-Atari
system equipped with a SCSI interface. Since my knowledge of the hardware
technicalities of hard disks is fairly scant, I'm going to air my
ignorance here in the hope that I can learn something.
The drive is a Megafile 30, using a Seagate ST238R. The controller board
is rev 2.1 and is labelled 'RLL with SSI'.
1. RLL is a means of formatting a disk to obtain more space at a slight
time penalty, isn't it? Is it a modulation technique (like MFM)?
Can it be used with any drive?
2. My understanding is that a hard drive for the Atari ST needs three
things: a host adaptor (which converts the ST DMA interface to SCSI),
a disk controller card (various Omti and Adaptec part numbers are bandied
about), and the drive itself. The controller card can be omitted when
the drive has embedded SCSI. If I've got this right, it seems that the
'controller' board in the Megafile combines the first two functions.
I'll need to bypass the host adaptor part. Any tips?
3. 30MB isn't much, and the ST238R isn't fast, so at some point in the
future I'll probably want to swap it for a bigger/faster unit (or add
a second drive). What will I need to know when choosing which drive
to buy?
4. Am I wasting my time? Would it be cheaper to sell the Megafile intact
and buy a drive with embedded SCSI? (I already have various PSUs lying
around).
Thanks in advance,
Malcolm
--
Malcolm Ray
City of London Poly Computer Service, 100 The Minories, London EC3N 1JY ENGLAND
JANET: M.Ray@uk.ac.clp
Internet/BitNet/EARN: M.Ray@clp.ac.uk
uucp: ...!ukc!clp.ac.uk!M.Raycsbrod@medusa.informatik.uni-erlangen.de (Claus Brod ) (05/07/90)
MALCOLM@tower-vax.city-poly.ac.UK writes: >1. RLL is a means of formatting a disk to obtain more space at a slight > time penalty, isn't it? Is it a modulation technique (like MFM)? > Can it be used with any drive? RLL is a modulation technique, that's right. Drive manufacturers tell you not to use RLL controllers with drives that aren't RLL-certified. You can, however, use many MFM drives with an RLL controller, but nobody guarantees you it will work. >2. My understanding is that a hard drive for the Atari ST needs three > things: a host adaptor (which converts the ST DMA interface to SCSI), > a disk controller card (various Omti and Adaptec part numbers are bandied > about), and the drive itself. The controller card can be omitted when > the drive has embedded SCSI. If I've got this right, it seems that the > 'controller' board in the Megafile combines the first two functions. > I'll need to bypass the host adaptor part. Any tips? You've got it quite well. Nevertheless, I don't know any way to bypass the host adaptor part of the Megafile's controller board since both parts have been combined. You might try to get a stand-alone Adaptec RLL controller from Adaptec or from an old SH204, but I guess it'll be cheaper and easier for you to get a real SCSI drive and sell your Megafile. Claus Brod
freak@salyko.cube.sub.org (Alexander Reinelt) (05/08/90)
MALCOLM@tower-vax.city-poly.ac.UK writes: >3. 30MB isn't much, and the ST238R isn't fast, so at some point in the > future I'll probably want to swap it for a bigger/faster unit (or add > a second drive). What will I need to know when choosing which drive > to buy? Well, I don't know much about hardware, but I can tell you about this point. It is possible, and not a bad idea, to put a second drive into the megafile 30 and on the hostadaptor of it. (Hope you get my english...) Well, there are lots of people in the atari.ger.fido (Fido Nets Atari Board in germany) who discussed this problem some time ago. I myself want to put a new, second drive in my megafile, as soon as i got the money. I think about 60 MB, 3,5" and RLL. Well, the hardware in the megafile is in some way ready to accept a second unit ! I can't tell you exactly, but there shurley many people out who know... The software is the other prob - AHDI is, as far s I know, not prepared for a second unit. And it has some bugs besides that point ... I use CBHD SYS. This is a very nice hard disk driver. It is based on the AHDI and rerwritten and very improved by a german called CLAUS BROD. He wrote aa nice and good book about floppies, harddisks etc on the st and inculded a disk within the book. This driver allows you without any problems to access a second unit in the megafile 30 or to boot from the partition you want (up to 12 are possible i think)... Well, overall its a great thing. Claus Brod is unfortunately no more contactable via usenet, but maybe I could help you a bit... c u, Freak ..................................................................... : Freak happens to be Alex Reinelt from Munich/West-Germany : # contact: freak@salyko.cube.sub.org ((Fido-adress is altering)) # : ~~~~~~~~~~~~~~ direct & vocal: +49-89 68 33 40 ~~~~~~~~~~~~~~~ : ! Life is a full time occupation - why let it be a situation vacant ? :...........................................(Rupert Hine/Thinkman)..: