Disk hardware used at U-M

posted Jun 8, 2014, 4:57 AM by Jeff Ogden   [ updated Jun 8, 2014, 1:21 PM ]
On Jun 8, 2014, at 1:08 AM, Mike Alexander wrote:

I do know the answers to some of these questions (as I'm sure Gary does too).  Comments appear below.  They were somewhat hastily entered so may have mistakes.


--On June 7, 2014 at 9:28:49 PM -0400 Jeff Ogden <jco@umich.edu> wrote:

And what was the hardware evolution of the disks? Did MTS ever use
2311s? I'm sure that 2314s were used. I assume that that was followed
by 3330s, 3330-IIs, and then 3350s. Were 3350s the first
non-removable disks (ignoring the 2301 drum and 2305 fixed head file)
we used?  We had various brand-X disks (ITEL, Memorex, Amdahl, ...),
but I think they were all compatible with some model of IBM disk.
Were the Amdahl disks the first to have a native mode of their own or
at least the first to have a native mode that we used?

The first disks were 2311s.  I think we used all the others you mention as well as a few oddball ones.  Do you remember the super disk with for spindles and one actuator in a large case.  MTS drove it so hard that it essentially melted and we were down for several days while the vendor (I forget now who it was) flew in a new one.

These disks all emulated IBM disks, but some also had a native mode which MTS could use.  This wasn't common, and I can't remember the details, but I'm sure there are tables in the distributions that would fill in some of these blanks.

Did I miss anything? What came after the Amdahl disks?

More IBM disks, probably 3390s of some flavor.  By then we were very definitely an all-IBM shop.

On Jun 8, 2014, at 1:23 PM, Mike Alexander wrote in response to several comments and questions from Jeff:

On Jun 8, 2014, at 10:34 AM, Jeff Ogden wrote:

Thanks Mike.
. . .
I know the file routines supported FBA [fixed block architecture] devices. Did U-M ever have any FBA disks?

Yes, we had support for several FBA devices.  It wasn’t hard since the file system used a fixed block size by then.

That same issue of Computerworld has an article about the Superdisk on page 1.  There were two models, the largest of which had a capacity of 800 MB, which was quite large for the time.