cwright@wpi.WPI.EDU (Charles R Wright) (12/29/90)
Please pardon me if this has been covered before. I have a friend with no news access who would like to know about the following: Essentially, is a SCSI drive a SCSI drive is a SCSI drive? Does Apple do any "weird shit" to make their "SCSI" drives incompatible with any other manufacturer? Specifically, can a third-party Mac SCSI drive be connected to a Next machine's SCSI port? For that matter, can one connect it to a Sun with SCSI port? Please respond directly by email as I don't often read these groups. Charles Wright cwright@wpi.wpi.edu
cwright@wpi.WPI.EDU (Charles R Wright) (01/04/91)
It seems many people out there are interested in this topic
(understatement?) so I decided to post the responses I got.
Generally, people gave varying answers depending on which drive they
tried, and what exactly they wanted to achieve. I hope people find
the answers useful; I'm not exactly sure how useful they are as I am
not involved in this kind of work at the moment.
All standard dislaimers apply! I'm not responsible for your computer
blowing up! ;-)
Charles Wright
cwright@wpi.wpi.edu
======================================================================
From: maltasr@csusac.ecs.csus.edu (Robert Maltas)
Message-Id: <9012290143.AA14492@csusac.ecs.csus.edu>
To: cwright@wpi
Subject: Re: Compatibility of Mac SCSI drives with other systems
Newsgroups: comp.sys.next,comp.periphs.scsi,comp.sys.mac.hardware
In-Reply-To: <1990Dec28.210746.21876@wpi.WPI.EDU>
Organization: California State University, Sacramento
Status: OR
Depends on what type of MAC SCSI drive you purchase. I bought a
PowerDrive 210 meg external SCSI drive; it uses a Quantum
ProDrive 210S and was meant to be used for a MAC-----------but
I'm using it on my Amiga 2000, with no problem at all.
Robert Maltas
--
///
\\\/// UUCP : {ucdavis|lll-crg}!csusac!maltasr
\XX/ Internet: maltasr@csusac.csus.edu
======================================================================
From: eps@toaster.SFSU.EDU (Eric P. Scott)
Message-Id: <9012290149.AA05057@toaster.SFSU.EDU>
To: cwright@wpi
Subject: Re: Compatibility of Mac SCSI drives with other systems
Newsgroups: comp.sys.next,comp.periphs.scsi,comp.sys.mac.hardware
In-Reply-To: <1990Dec28.210746.21876@wpi.WPI.EDU>
Organization: San Francisco State University
Reply-To: eps@cs.SFSU.EDU
Status: OR
In article <1990Dec28.210746.21876@wpi.WPI.EDU> you write:
>Essentially, is a SCSI drive a SCSI drive is a SCSI drive? Does Apple
>do any "weird shit" to make their "SCSI" drives incompatible with any
>other manufacturer?
YES!
> Specifically, can a third-party Mac SCSI drive be
>connected to a Next machine's SCSI port? For that matter, can one
>connect it to a Sun with SCSI port?
Sun and NeXT devices should be interchangeable, Mac peripherals
often don't work with either. Sometimes a ROM change will fix
things, sometimes not. Talk to your vendor.
BTW, at least 80% of all "stupid questions" are answered in
NextAnswers--the first place you should look! Here's a sample:
Q: I have a Maxtor XT-8760S for a Mac. Can I use it with my NeXT?
A: No. According to Maxtor, they make different versions of the
same model of drive for different computers. The Mac version of
the 8760S, for example, has a different PROM to handle Apple's
non-standard SCSI implementation. The Mac PROM is incompatible
with our computer.
Contact Maxtor for more information.
QA574
-------
SCSI disk compatibility Release 2.0
Q: What SCSI hard drives are compatible for use with NeXT computers?
A: NeXT offers a complete line of hard disks for use with NeXT
computer systems. They range in size from 105 MB to 1.2 GB.
These drives have been carefully qualified by NeXT and include
NeXT's one year warranty. You should contact your authorized
NeXT reseller for more information on these drives.
The NeXT system software also supports some third party SCSI hard
drives not sold by NeXT. For the NeXT system software to support
the drive your system must be running software release 2.0, be
connected to the drive with the correct cable, and the drive must
support the following SCSI commands and revisions:
1) "Inquiry" and "Read Capacity" commands
2) The drive must conform to the ANSI SCSI Rev. 17B or greater
3) 10 (ten) byte read and write command blocks
If the drive is unformatted, it will be automatically formatted
only in the following situations:
--the drive's capacity is less than 6 MBytes, and
--the drive uses removable media.
In order to work with the file system, the drive's sector size
must be 512 or 1024 bytes.
Please check with your SCSI drive provider for details on your
drive. NeXT does not have additional information on third party
drives.
See also: QA579 regarding SCSI cables.
QA586
-=EPS=-
======================================================================
From: matthews@is-next.umd.edu (Mike Matthews)
Message-Id: <9012290020.AA14523@is-next.umd.edu>
To: cwright@wpi
Subject: Re: Compatibility of Mac SCSI drives with other systems
Newsgroups: comp.sys.next,comp.periphs.scsi,comp.sys.mac.hardware
In-Reply-To: <1990Dec28.210746.21876@wpi.WPI.EDU>
Organization: Comp. Sci. Ctr., Univ. of MD, College Park, MD 20742
Cc:
Status: OR
In article <1990Dec28.210746.21876@wpi.WPI.EDU> you write:
>Please pardon me if this has been covered before. I have a friend
(stuff deleted)
>cwright@wpi.wpi.edu
As long as it's external, and you have the right cable, it will be no problem
at all.
Internal drives may be kind of funky, though, since Mac *does* do something
funny with the SCSI signal. It only seems to matter for internal setups, though
(I have no idea why). I bought a "Mac" Fujitsu drive, and it works peachyfine
on my NeXTstation.
Mike
======================================================================
From: Jim Guyton <guyton@gaucho>
Message-Id: <9012290817.AA00677@gaucho.rand.org>
To: cwright@wpi
Subject: Re: Compatibility of Mac SCSI drives with other systems
In-Reply-To: <1990Dec28.210746.21876@wpi.WPI.EDU>
Organization: The RAND Corporation, Santa Monica, CA
Status: OR
In article <1990Dec28.210746.21876@wpi.WPI.EDU> you write:
>
>Essentially, is a SCSI drive a SCSI drive is a SCSI drive? Does Apple
(stuff deleted)
>connect it to a Sun with SCSI port?
>
You can (mostly) mix and match (subject to funny cables, the real
internal scsi cable is standard, but the external cables are wide
and varied). The biggest problem I've found is that the Mac Boot
proms aren't quite up to spec. It resets the bus, and then does a
read of the boot block. But a lot of disks go into a wierd 'query me'
mode after a reset and need to have their status read before a block read
will work. I.e. a slight difference in the drive roms makes life
anything but boring.
I have lots of fun mixing/matching scsi disks between Suns and Macs, haven't
ever used a Next machine.
-- Jim Guyton
guyton@rand.org
======================================================================
From: finger@evax.utarl.edu (Jay Finger)
Message-Id: <9012290700.AA14004@evax.utarl.edu>
To: cwright@wpi
Subject: Re: Compatibility of Mac SCSI drives with other systems
Newsgroups: comp.sys.next,comp.periphs.scsi,comp.sys.mac.hardware
In-Reply-To: <1990Dec28.210746.21876@wpi.WPI.EDU>
Organization: Computer Science Engineering Univ. of Texas at Arlington
Cc:
Status: OR
When Apple first started using SCSI, they botched it up. They've fixed
it since then, but many some drive manufacturers still sell normal and
mac versions of their SCSI drives. Other drives are compatible both
ways, still others only work with normal SCSI and run the risk of not
working with Macs (but it's been a while since I've found one like
that).
I'm going to try to use a Quantum 80Meg drive that used to be on a
macintosh (an old mac that had some of the apple screw-ups) with my
NextStation (105Meg). I don't know if it will work with the station
yet, because I don't have the correct cable. However, 3 days ago I
connected it to a NeXTCube that had the old 68030 board (with mac-style
connector) and was running NeXTStep 2.0. Everything worked great, I
copied over the development stuff that I don't have, so I'm pretty
optimistic that once I get the cable I'll be able to use the drive.
If your friend is trying to use an 80Meg Quantum let me know, and I'll
try to remember to let you know what happens once I get the cable.
----
#include <stddisclaimer.h>
Jay Finger
Computer Science and Engineering, University of Texas at Arlington
finger@evax.utarl.edu
b645zai@utarlg.utarl.edu
======================================================================
From: dce@krusty.smsc.Sony.COM
Received: from krusty.smsc.Sony.COM by sonyusa.Sony.COM (4.0/SMI-4.0)
id AA09852; Mon, 31 Dec 90 09:40:43 PST
Date: Mon, 31 Dec 90 09:40:43 PST
Message-Id: <9012311740.AA09852@sonyusa.Sony.COM>
To: cwright@wpi
Subject: Re: Compatibility of Mac SCSI drives with other systems
Newsgroups: comp.sys.next,comp.periphs.scsi,comp.sys.mac.hardware
In-Reply-To: <1990Dec28.210746.21876@wpi.WPI.EDU>
Organization: Sony Microsystems Corp, San Jose, CA
Content-Type: text
Content-Length: 1534
Status: OR
In article <1990Dec28.210746.21876@wpi.WPI.EDU> you write:
>Essentially, is a SCSI drive a SCSI drive is a SCSI drive? Does Apple
(stuff deleted)
>connect it to a Sun with SCSI port?
Apple SCSI isn't a complete implementation, but the problems almost
always go in the other direction. That is, a drive not set up
specifically for a Mac may not work in a Mac. I recently got a great
deal on a pair of CDC hard disks (150MB external drives for $300
each!). It worked fine on my Mac II (I was lucky enough to have some
formatting software that knew about the drive), but on a friend's Mac
Plus, it wouldn't work as the boot drive (which was what he wanted it
for in the first place). He had to do a lot of work getting the
termination right by adding resistors, moving jumpers, and so forth,
but eventually got it all working. Luckily, his Plus was not one of
the tan/beige ones, which had more problems with many standard SCSI
drives.
So, it is probable that your 3rd-party drive will work fine with the
NeXT or Sun, or any Unix machine, as long as you can get the parameters
for the drive (which can be the hard part, especially with smaller
drives, since most Unix machines are set up for big drives).
--
...David Elliott
...dce@smsc.sony.com | ...!{uunet,mips}!sonyusa!dce
...(408)944-4073
..."That's *Mr.* Squishy-Lips to you!"
======================================================================
To: cwright@wpi (Charles R Wright)
Subject: Re: Compatibility of Mac SCSI drives with other systems
From: johankha@tz.wimsey.bc.ca (e_mou)
Message-Id: <0NF2u1w163w@tz.wimsey.bc.ca>
Date: Mon, 31 Dec 90 01:46:32 PST
In-Reply-To: <1990Dec28.210746.21876@wpi.WPI.EDU>
Organization: Somewhere in The Twilight Zone, Van, B.C
Status: OR
cwright@wpi.WPI.EDU (Charles R Wright) writes:
> Please pardon me if this has been covered before. I have a friend
(stuff deleted)
> cwright@wpi.wpi.edu
I managed to get an EMAC Metro external hd to hook up to a cube. You need
to edit the disktab, but it seems to be working fine. (This was done about
4 weeks ago).
======================================================================
From: mlg@cblph.att.com (Michael L Goodrich)
To: cwright@wpi
Subject: Re: Compatibility of Mac SCSI drives with other systems
Newsgroups: comp.sys.next,comp.periphs.scsi,comp.sys.mac.hardware
In-Reply-To: <1990Dec28.210746.21876@wpi.WPI.EDU>
Organization: AT&T Bell Laboratories
Cc:
Status: OR
In article <1990Dec28.210746.21876@wpi.WPI.EDU> you write:
>Please pardon me if this has been covered before. I have a friend
(stuff deleted)
>cwright@wpi.wpi.edu
As far as I know apple doesn't do anything unusual with there implementation
of SCSI. I have used various hard drives from a buch of different manufacturers
with my Mac Plus and have only had problems with the HP drives. Other than that
everything has worked very well.
Thanks
Mike
mlg@cblph.att.com
======================================================================
From: Donald Phillips <DonP%blkhole.uucp@RELAY.CS.NET>
To: cwright@wpi
Subject: Re: Compatibility of Mac SCSI drives with other systems
Status: OR
>Essentially, is a SCSI drive a SCSI drive is a SCSI drive? Does Apple
(stuff deleted)
>connect it to a Sun with SCSI port?
I haven't tried connecting Mac SCSI devices to other computers, however I have
successfully connected a Maxtor Hard Disk and an Exabyte tape drive to a
Mac IIci's SCSI port.
__
Donald Phillips
Research Unlimited
Escondido, Californiats@cup.portal.com (Tim W Smith) (01/04/91)
Some observations and questions: 1. If you buy a drive packaged in an external case, rather than a raw drive, you may want to check the cabling. Some vendors cut the reset line. This can cause problems with some software. 2. When in doubt, check to make sure termination power is being supplied by someone. This is most likely to be a problem when going from something else to a Mac plus. 3. Someone said Next requires drives to support the 10 byte read and write commands. Why is this? It takes less than 10 lines of code to make your software work correctly on both drives that don't support 10 byte commands and those that do, with the only runtime penalty being an AND and a branch. Is there any rational reason not to include this? 4. The special support some vendors provide for the Mac is usually an option to not do a UNIT ATTENTION after reset. This is often selectable via MODE SELECT. I've seen some drives (although I don't remember which ones they were) where this was done, although the MODE SELECT page that controlled this was not documented by the drive manufacturer. They sold two models of drive, one for Mac and one not. The only difference between them, I believe, was the setting of this undocumented option. 5. The Mac does not put many demands on a SCSI drive as far as software goes. If the drive has quirks that could cause problems on other systems, these quirks might not show up on the Mac, but would show up on other systems, thus preventing that drive from working on non-Macs. For example, the 40 meg Sony that Apple bundles with many of their machines works fine on the Mac. It will fail on some other systems because Sony screwed up their SCSI implementation. I don't remember the exact details, because it's been a few months since I found this, but what happens is something like this: Initiator selects Sony with ATN. Sony fetches the IDENTIFY message. Initiator still has a message to send (negotiation for synchronous data transfer), so Sony asks for this message. After receiveing the first byte, the Sony changes to MSG_IN phase and sends a REJECT message. Sony then goes into MSG_OUT phase. Initiator sends a NOP message. Sony drops BSY! Tim Smith