In article <pgk4svccqeficp8vkq1hjb0ripaeb8qs3h@4ax.com>,
Claus Dragon <claus@ultima-dragons.org> wrote:

> why the boot drive has the number 3 instead of 0 or even 1 will be
> forever beyond my understanding.

I explained in an earlier article in this thread.

| Boot from SCSI ID 3 was introduced
| with the first Sun4c systems (SPARCstation 1) as Sun assumed that
| buyers of these systems wanted to continue to use their external disk
| drives (sun3 desktop systems like the Sun 3/50 didn't have internal
| disks) from their sun3 systems. The external disk drives used with sun3
| systems required that it be opened to change the SCSI ID, so Sun
| thought that making the internal disk of the Sun4c systems be SCSI ID 3
| would make it easier for their customers.

--
Göran Larsson http://www.mitt-eget.com/

On Monday 24 November 2003 6:47 pm in comp.sys.sun.hardware Claus Dragon
wrote:

> While forming in a straight line, Chris Newport
> <me@see-my-sig.invalid> wrote:
>
>>Sun machines have a standard for SCSI ID which you should obey.
>
>>1st/boot drive = 3
>>2nd drive = 0
>
> why the boot drive has the number 3 instead of 0 or even 1 will be
> forever beyond my understanding.

Someone else explained this a few days ago.
Basically the Sparc 1 (?) was the first Sun box to have an internal
drive. Sun realised that people would want to keep the external
drives that they had from previous models, but these needed
disassembly to change the SCSI ID. Sun therefore chose the least
used ID 3 for the internal drive, and this persisted until the
Ultra range was released and sanity was restored.
IOW, it seemed like a good idea at the time.

--
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While forming in a straight line, hoh@invalid.invalid (Goran Larsson)
wrote:


>> why the boot drive has the number 3 instead of 0 or even 1 will be
>> forever beyond my understanding.
>
>I explained in an earlier article in this thread.

aaah, okay.

so basically, they used that system because it was introduced earlier,
especially for external disks.

thanks for pointing that out
--
Claus Dragon <clauskick@mpsahotmail.com>
=(UDIC)=
d++ e++ T--
K1!2!3!456!7!S a24

In article <7it5sv8ai7co4o7d3j909iorv83ajs4jt9@4ax.com>,
Claus Dragon <claus@ultima-dragons.org> wrote:

> so basically, they used that system because it was introduced earlier,
> especially for external disks.

No. The earlier systems (sun3) did boot from SCSI ID 0, but as sun3
desktop systems did not have internal disks they booted from a disk
in an external box.

The new desktop systems (sun4c) did boot from the least used SCSI ID,
3, an internal disk. This was done to make it possible for the
customer to re-use the external disks from their old system without
having to open up the boxes and moving SCSI ID straps. Remember, disks
were not cheap at that time so the customer was probably going to
keep his old disks.

--
Göran Larsson http://www.mitt-eget.com/