PDP-11 SCSI drive choices...

From: Fred N. van Kempen <waltje_at_pdp11.nl>
Date: Fri Jan 9 16:41:14 2004

On Fri, 9 Jan 2004, Christopher Cureau wrote:

> Forgot to mention in my last mail...I need to get a disk, but I'm not sure
> how 2.11BSD will react to it. Should I limit its size? Any
> recommendations?
Well, most systems dont care, but it *helps* to have them be around
the size ("at least as large as") an existing drive which the controller
will emulate.

For example, if your SCSI controller emulates a KDA50 MSCP controller,
it will tell the software that it has a bunch of RAxx drives attached
to it. It then *helps* to have a SCSI drive which is at least as
large as the RAxx drive it emulates:

RA80 - 206MB
RA81 - 456MB
RA82 - 622MB

which are mere examples. So, get a SCSI drive of, say, 240MB (those
extremely cheap Quantum LPS240's - they cost $0.50 a piece where I
come from ;-) and have the controller emulate them as being RA80's.

Get a cheap 540MB disk (Conner, Quantum, IBM, Seagate) and have it
emulated as a RA81, and so on.

Although it is possible, *not all operating systems* will actually
*ask* the drive how large it is: many will *assume* a size when the
drive type is known...

One of my friends in Holland actually uses a nunch of SCSI-based
IOmega JAZ drives for this purpose: 1GB per disc cartridge, and he
can plug and play....

Fred N. van Kempen, DEC (Digital Equipment Corporation)
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Email: waltje_at_pdp11.nl     BUSSUM, THE NETHERLANDS / Mountain View, CA, USA
Received on Fri Jan 09 2004 - 16:41:14 GMT

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