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Re: Larger memory option for VAXstations

On 2015-08-18 22:06, John Klos wrote:

I was looking around at 100 Mbps ethernet cards for VAXstations and came
across a product catalogue from a company called Nemonix. It lists
products such as 100 Mbps ethernet and UW-SCSI expansion boards and
other neat products, but most interestingly it lists a 512 meg upgrade
kit for VAXstation 4000/90 (90a or 96) systems as eight 64 meg SIMMs.

It doesn't seem as if the memory is available separately from an
upgraded motherboard they sell, but it appears that the upgrade provides
2 megs of cache and synchronous SCSI (up to 10 MB/sec) in addition to
the ability to handle up to 512 megs of memory.

Does anyone have any hardware information about VAXstation 4000/90(a or
96) motherboards which would help figure out how we might be able to get
512 megs?

Faster SCSI wouldn't be so bad, too :)

I don't have any hardware information, but an educated guess would be that you need some additional address lines routed from the CPU to the memory sockets. The CPU itself have the necessary address lines on pins, but unless they also go to the memory sockets, you cannot get that high in memory. But from a CPU point of view, there is nothing speical about going to 512 Megs. Or even more. But if you go for more physical memory, you need an NVAX (which I think the 4000 machines have), and the OS needs to change the mode of the CPU, which I suspect VMS will not do on a 4000 machine, as they would not expect you to have that amount of physical memory that would require changing from the default mode.

Of course, we could do that in NetBSD, but I don't think we support a single NVAX type machine yet...


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