VAX 780 on eBay

Zane Healy healyzh at
Mon Jan 3 10:49:45 CST 2022

On Jan 2, 2022, at 9:18 PM, Warner Losh <imp at> wrote:
> I had accounts on a MicroVAX 2 and a VAX 11/750. The microvax was faster for most compute jobs, but the 750 with 1/4 the memory handled more users mostly in text editors with the occasional compile or nroff/troff jobs. IIRC, the 750 had faster disks...
> Warner

I picked up a copy of “VAX I/O Subsystems: Optimizing Performance”, it gives I/O speeds for SDI and DSSI disks, I don’t doubt that the VAX-11/750 had faster disks if it had RA81 or especially RA82 disks.

Here we go, from the HP "OpenVMS I/O Users Reference Manual” for 7.3-1.
"On VAX systems, the RD53 and RD54 are 5.25-inch, full-height, Winchester-type drives with average access time of 38 ms and a data transfer rate of 0.625 MB per second.”

Even the RA80 can beat that, basically any SDI disk on a VAX-11/750 would be noticeably faster.  There is a reason why MicroVAX I and II systems with RD53/54 drives were considered to be good for Performance Tuning training.  It’s really easy to notice improvements.


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