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From: hojo@cbnewsb.cb.att.com (HC Johnson)
Newsgroups: comp.sys.atari.st
Subject: chaining hard drives to a 1040ST
Keywords: ST, hard drives, chaining
Message-ID: <1991Feb13.183757.9927@cbfsb.att.com>
Date: 13 Feb 91 18:37:57 GMT
Sender: news@cbfsb.att.com
Organization: AT&T Bell Laboratories
Lines: 30



> What is the maximum number of hard drives that can be chained together
> on a 1040ST (TOS 1.0)?  Is there any problem with having different sized
> hard drives (e.g. 2 20meg and a 30meg)?  Is there a ceiling on the
> amount of disk space TOS will recognize?  Is the number of partitions
> limited only by the number of letters in the alphabet, or is there a TOS
> limit on the total number of HD partitions?
> 
> Steve "Stevers!" Coile
> {scoile|acs075}@gmuvax[{.BITNET|[2].gmu.edu}]|2211c1@gmuvax2.gmu.edu
> "Maturity is knowing when and where to act immature"
> 
> 
The TOS limit: 16 devices, of which 2 are the floppy drives.
This leaves 14 HD partitions which can be active at one time.

The 1040ST limit: At most 7 SCSI devices.  Most of these support
2 Hard Drives, some 8.  Subtract 1 SCSI device for the (usual) clock,
and you get 6, giving 12 to 48 drives maximum.


The Atari Hard disk driver, AHDI, only supports 1 HD on each SCSI device.

Thus TOS will access disk like devices as letters C thru P.

Howard Johnson
ATT BELL LABS
att!lzsc!hcj
hcj@lzsc.att.com