[rescue] Rescued VAX 4500 question

Scott Newell newell at cei.net
Thu Jun 13 23:09:35 CDT 2002


>yes, it has those things, as well as up to 4MB ram in some cases, ethernet in
>most cases, disks, tape drives, what do you want to hook up to it?  you
probably
>can.

Jeez, that sounds nothing at all like the systems I've seen.


>> collectable (hell, I'd still like to have an HP-85), but that's a lot of
>> heat and space for what sounds like an awfully slow and limited machine.
>
>slow by what standards?  i've got a PDP-11/83 that is going to be a DECnet

The XINU book mentions that the interrupt dispatcher prescales the 60Hz RTC
rate down to 10Hz, because it can't keep up at 60Hz.  Considering the XINU
is a pretty light OS, well, I assumed that it (they call it an LSI 11/2 ?)
must be a pretty slow machine.  And that's all I'm going on...just a single
excerpt from an old book  (I've run 68HC11 in embedded products,
multitasking, with >50Hz tickers, so it really jumped out at me when I
first read it.)

Now maybe what I'm calling an embedded LSI-11 system is really some
seriously cut-down, bare-bones, low-end implementation?  When I think
PDP-11, I think racks full of stuff, and that's a long way from what ran
these little milling machines.


newell



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