[Simh] CI750 tech docs and VAX firmware

[Johnny Billquist]

On 2017-03-07 02:21, Tim Stark wrote:
> Hmm, interesting.  K.scsi is not mentioned in my HSC50/70 docs.  Does anyone have any docs contains K.scsi tech info?

I don't. I have no technical information on any of the modules. But I do 
know that your HSC90 documentation have a bit of information about the 
upgrade to be able to use SCSI. But it's mostly about how to install the 
stuff.

	Johnny

>
> Thanks again,
> Tim
>
> -----Original Message-----
> From: Simh [mailto:simh-bounces at trailing-edge.com] On Behalf Of Johnny Billquist
> Sent: Monday, March 6, 2017 6:47 PM
> To: simh at trailing-edge.com
> Subject: Re: [Simh] CI750 tech docs and VAX firmware
>
> On 2017-03-06 15:03, Timothe Litt wrote:
>> There were also HSC40 & hsc60.
>
> Right. Pretty similar to all the others. The differences (as far as I can remember) were mostly on the number of SDI/STI ports available, and the amount of cache in the machine.
>
>> The differences in the hsc family members were the processor, cache,
>> load device, number of channels, and maximum number of ports.  Some
>> models were field-upgradable.  Also, later models supported
>> (reluctantly) the K.scsi module, which allowed the HSC to serve SCSI
>> disks and tapes.  (SCSI was carefully analyzed & found to have
>> reliability/data integrity issues; DEC's answer was DSSI.  Rather like
>> Beta & VHS - "good enough, but cheaper" won.)
>
> Right. However, to use the K.scsi, you actually needed to upgrade. The
> HSC90 with the capability to use K.scsi was the HSC95. I don't think the
> HSC70 could at all. The 40 and 60 could, I think, but I wonder if they then were renamed 45 and 65. I think I still have some documentation somewhere, but it would take some digging to find this.
>
>> At some point, support for 18-bit disks (576 byte sectors) was dropped.
>> The HSC50 definitely had it; the HSC90 did not.  I'm unsure about the HSC70.
>
> Unless I remember totally wrong, only the HSC50 could do 576 byte sectors. It was dropped in a pretty early version of CRONIC, before support for any other HSC controller existed.
>
> 	Johnny
>
>
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-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol