[Info-vax] Why it is a good idea that OpenVMS isn't on x86-64 just yet

[Johnny Billquist]

On 2016-01-18 23:20, Norm Raphael wrote:
>   > On 01/18/16, Hans Vlems via Info-vax<info-vax at info-vax.com> wrote:
>   >
>> John, what on earth did you do wrong to deserve that???
>> The TU58 was probably cheap, certainly less expensive than the RX02 on the 11/780 along with its LSI-11.
>> The 11/750 had to be slower than the 11/780 because DEC had announced an entry level VAX.
>> The gate array technology was rather new and I think
>> engineering was pleasantly surprised with the end result. Marketing must have felt a different emotion...
>> The 11/750 cpu ran slower than the 11/780. At 0.6 VUPS it was twice as fast as the 11/730.
>> Its only advantage was its small size, roughly a pdp 11/40 cabinet, a lot smaller than the
>> 11/750 and no a/c required.
>> Two TU58 drives didn't really help either.
>
>
> TU58's used the DISK DRIVER, not the tape driver, so they blocked disk I/O when in use.  Slow doesn't
> really convey it.

That was not necessary. We're talking about the ACP here, which would 
only be involved if the TU58 was in Files-11 format. If it was in RT-11 
format, you mounted it foreign and used EXCHANGE.
Second, I'm sure you could use a separate, unique ACP for the TU58, just 
like in RSX, to keep it separated from all other system activity.
Third, I'm sure that for plain operations reading/writing blocks, it did 
not even block the ACP, unless VMS was more silly than RSX.

	Johnny

-- 
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