3 Apr
2011
3 Apr
'11
2:41 p.m.
From: joe heck <trash3 at splab.cas.neu.edu>
I have a 3100 model 80 with a failing disk drive. The two drives in it now are Seagate
ST15150N (I believe). I have a couple of questions:
Are there NEW drives out there that will work with this VAX?
What do I need to do to make a drive format/work?
Joe, I have quite a few small SCSI drives in my collection, but no
ST15150N drive. What capacity do you need?
--
Michael Thompson
4 Apr
4 Apr
3:21 p.m.
-----Original Message-----
From: cctalk-bounces at classiccmp.org [mailto:cctalk-
bounces at classiccmp.org] On Behalf Of Michael Thompson
Sent: 03 April 2011 22:41
To: cctech at classiccmp.org
Subject: Re: Vax 3100 disk recommendation and suggestions
ST15150N
From: joe heck <trash3 at splab.cas.neu.edu>
I have a 3100 model 80 with a
failing disk drive. The two drives in it now are Seagate ST15150N (I
believe). I
have a couple of questions:
Are there NEW drives out there that will work with
this VAX?
What do I need to do to make a drive format/work?
Joe, I have quite a few small SCSI drives in my collection, but no drive. What capacity do you need?
--
Michael Thompson
Can someone remind me what the formula is for working out whether a disk is
small enough for the older MicroVAX 3100s? I seem to remember it is an
absolute number of 512-byte blocks. I know it is about 1GB, but I am pretty
sure it can be slightly over, but I am never sure exactly how much you can
go over. I am always on the look out for disks small enough for these
machines.
Regards
Rob
4:28 p.m.
On Mon, Apr 4, 2011 at 3:21 PM, Rob Jarratt <robert.jarratt at ntlworld.com> wrote:
Can someone remind me what the formula is for working out whether a disk is
small enough for the older MicroVAX 3100s? I seem to remember it is an
absolute number of 512-byte blocks. I know it is about 1GB, but I am pretty
sure it can be slightly over, but I am never sure exactly how much you can
go over. I am always on the look out for disks small enough for these
machines.
If the restriction comes from the host only using SCSI Read(6)
commands then the limit is a 21-bit Logical Block Address (LBA) field.
SCSI Read(10), Read(12), and Read(16) have larger LBA fields.
http://en.wikipedia.org/wiki/SCSI_Read_Commands
With a 21-bit LBA the host can access 2,097,152 blocks.
If those blocks are 512 bytes each that works out to a total of
1,073,741,824 bytes.
-Glen
5011
days inactive
5012
days old
2 comments
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glen.slick＠gmail.com -
michael.99.thompson＠gmail.com -
robert.jarratt＠ntlworld.com