Mac Plus & SCSI

[patrickg53]

I want to raise a question to this expert forum :

I own from 1989 a Mac Pus, acquired at that time as a "used" machine upgraded from a Mac 512 by the original owner.

I bought in 1990 a 40 Mb external hard disk that fit in a metal box standing just under the Mac Plus.

Two years ago, the hard disk just died. I look around on ebay and had a lot of troubles finding a SCSI-1 disk under 1Gb. I found a Quantum Fireball ST2.1S that I inseted in the original box.

By that time, I was able to start again my Mac Plus using a 4Gb external disk containing a Quantum Fireball SE4.3S of 4,2 Gb : using the modified version of Apple HD SC Setup 7.3.5, I was able to create a partition of 400Mb with a system 7.1 dedicated for the Mac Plus. This assembly just boots fine. javascript:emoticon(':b&w:')

If I perform the same with the Quantum Fireball ST2.1S, the Mac Plus never boots, standing with an exclamation point.

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If I put the two disks on a SCSCI chain, the SE4.3S allows boot, and then the ST2.1S is mounted.

I just got a Quantum TRB850S, older, and same problem : no way of making it bootable.

javascript:emoticon(':-X')

By the way , I was never abale to use the "interleave hiden option of Apple HD SC Setup 7.3.5 : I got the acces thru the Command-I option, type 3 but all HD are still formatted with 1

Can anybody can provide any help or explaination ? [?]

 

[LCGuy]

Here is a webpage you may find of use. Give Lido or Silverlining a go, i believe both should run on a Plus. Obviously the drive is compatible with the Plus, since it mounts and all, so my advice would be to try different formatting software.

 

[Scott Baret]

Check the interleave ratio. 3:1 for a Plus, 2:1 for an SE/Classic, 1:1 for anything else. Silverlining, as LCGuy mentioned, should be able to get you through that process.

 

[LCGuy]

IIRC, though, doesn't Apple HDSC Setup automatically determine the correct interleave to use on the machine you're running? I think thats what I read in MacAddict a few years back, anyway...

 

[patrickg53]

IIRC, though, doesn't Apple HDSC Setup automatically determine the correct interleave to use on the machine you're running? I think thats what I read in MacAddict a few years back, anyway...

This is really the strange thing that occurs :

When I start Apple HD SC Setup on the Mac Plus, with my two disks connected (the one that is able to boot and the other one), tytping Command-I on the "bad" HD, I got an interlaved "2" appearing in the window; bingo : I start the init process... and after a while, I still got an interleave of "1" on that disk. Same try with 3.

By the way the disk that is able to boot with 4.2 GB is also formatted with interleave 1

Thanks for the advice

 

[tomlee59]

Here's what you're running up against: Most modern drives do not allow you to format at anything other than 1:1 interleave. So, HD SC Setup can make all of the requests it wants, but the drive's own controller will blithely ignore all requests to format at other than 1:1 interleave.

I'm actually amazed that you were able to get the Plus to boot off of a 4GB drive! That is a *very* rare achievement.

 

[equill]

... the Mac Plus never boots, standing with an exclamation point ...

Point interrogation, peut-être?

Your post reads as if you are enjoying termination problems. Older Quantum drives used three in-line resistor packs on the drive's logic board for 'passive' termination. SCSI ID was also fixed at 0, because the drive was conceived as being the only, and therefore also the physically last, drive in a daisy-chain that was inaccessible inside a never-to-be-opened box.

Time and taste moved on. Apple conceded that more drives in a daisy-chain might be permissible, and Quantum conveniently produced drives on which there were header blocks with three pin pairs, A0, A1 and A2, with which to select SCSI IDs from 0 to 6. SCSI 7 is reserved for a host controller, which is the Mac's controller here. ICs were added for 'active' termination, which was enabled or disabled with a jumper on an additional pin pair labelled TE. If such comparatively sophisticated drives and the older drives were placed in the same daisy-chain:

1) the older drive's terminating resistor packs had to be removed if it was not the physically last drive in the chain, but its SCSI ID could not be changed from 0 to anything else, or

2) the newer drive's terminating ICs had to be disabled if it was not the physically last drive in the chain, but its SCSI ID could be set as any one from 1 to 6.

It may be that your Quantum Fireball ST2.1S was/is not terminated, either with on-board resistor packs or with an in-place jumper. Hence the point interrogation when it alone is connected to the Plus and there is no external plug-in CN-50 terminator on the box. Conversely, the Quantum Fireball SE4.3S has a TE jumper, and works regardless of the presence of a CN-50 terminator on the box.

If you daisy-chain the two drives, fortuitously with the Quantum Fireball SE4.3S at the end of the chain, the lack of termination on the ST2.1S is just what you need when that drive is not physically the last in the daisy-chain, and it is therefore 'seen' by the system. This also argues that the SE4.3S drive is set with jumper(s) for a SCSI ID other than 0 or 7, which is also a fortunate happenstance.

Silverlining 5.6.x and 5.8.x will allow you to specify the necessary interleave ratio of 3:1 for set-up of your drives and, more importantly, to get it. They are both very close to the hardware, so proceed with circumspection in your use of them. Silverlining 2.2 has a better-developed GUI, and may be of use in conjunction with 5.8.x in showing you the hierarchy of drives, volumes and partitions (if you use partitions) during the process, and for later inspection of your setup.

de

 

[patrickg53]

Here's what you're running up against: Most modern drives do not allow you to format at anything other than 1:1 interleave. So, HD SC Setup can make all of the requests it wants, but the drive's own controller will blithely ignore all requests to format at other than 1:1 interleave.
I'm actually amazed that you were able to get the Plus to boot off of a 4GB drive! That is a *very* rare achievement.

It seems that you get the right answer : the disk drives do not accept the interleave = 1 option, as lesat as far as HD SC setup is concerned.

I will try to use others formatting software to check out if I can solve this problem.

I agree with you : I do not understand why this 4,2 GB HD is able to boot with my Mac Plus. The driver is register as ".ASC00" that seems to be the Apple HD SC setup one, and the interleave factor is 1 !

 

[patrickg53]

... the Mac Plus never boots, standing with an exclamation point ...

Point interrogation, peut-être?

de

Sorry, for this mistake : interrogation point of course. I am not using english currently at work these times, so is rather difficult for me to express myself in this language

is this ok : javascript:emoticon(':?:')

 

[patrickg53]

... the Mac Plus never boots, standing with an exclamation point ...

Your post reads as if you are enjoying termination problems. Older Quantum drives used three in-line resistor packs on the drive's logic board for 'passive' termination. SCSI ID was also fixed at 0, because the drive was conceived as being the only, and therefore also the physically last, drive in a daisy-chain that was inaccessible inside a never-to-be-opened box.

Time and taste moved on. Apple conceded that more drives in a daisy-chain might be permissible, and Quantum conveniently produced drives on which there were header blocks with three pin pairs, A0, A1 and A2, with which to select SCSI IDs from 0 to 6. SCSI 7 is reserved for a host controller, which is the Mac's controller here. ICs were added for 'active' termination, which was enabled or disabled with a jumper on an additional pin pair labelled TE. If such comparatively sophisticated drives and the older drives were placed in the same daisy-chain:

1) the older drive's terminating resistor packs had to be removed if it was not the physically last drive in the chain, but its SCSI ID could not be changed from 0 to anything else, or

2) the newer drive's terminating ICs had to be disabled if it was not the physically last drive in the chain, but its SCSI ID could be set as any one from 1 to 6.

It may be that your Quantum Fireball ST2.1S was/is not terminated, either with on-board resistor packs or with an in-place jumper. Hence the point interrogation when it alone is connected to the Plus and there is no external plug-in CN-50 terminator on the box. Conversely, the Quantum Fireball SE4.3S has a TE jumper, and works regardless of the presence of a CN-50 terminator on the box.

If you daisy-chain the two drives, fortuitously with the Quantum Fireball SE4.3S at the end of the chain, the lack of termination on the ST2.1S is just what you need when that drive is not physically the last in the daisy-chain, and it is therefore 'seen' by the system. This also argues that the SE4.3S drive is set with jumper(s) for a SCSI ID other than 0 or 7, which is also a fortunate happenstance.

de

I will need to cafefully read your analysis.

I know that both boxes have been opened by me in the past : the 2.1GB is replacement from a 40MB used only on this mac at home,

and the 4.2GB is a replacement from an external unit used on a Sun Sparc in my previous company.

This could explain but needs futher investigation and a screwdriver...

 

[tomlee59]

Bonne chance, patrick.

 

[equill]

Sorry, for this mistake : interrogation point of course. I am not using english currently at work these times, so is rather difficult for me to express myself in this language.

Il y a environ 55 années depuis j'ai étudié français, so your English is likely to be light-years ahead of my French. What matters is that you get on top of your termination mésaventures, as tomlee59 also encourages you to do.

de