[GTALUG] old computer / new computer

[Nicholas Krause]

On 9/2/21 4:18 PM, Lennart Sorensen via talk wrote:
> On Thu, Sep 02, 2021 at 12:04:51PM -0400, D. Hugh Redelmeier via talk wrote:
>> When I started playing with computers (1967) mainframes were the thing (we
>> called them computers).
>>
>> The University of Waterloo got an IBM SYSTEM/360-75, the biggest computer
>> in Canada, in 1967 or 1968.  It filled a lot of the "Big Red Room", a
>> jewel case the size of gymnasium.
>>
>> Eventually, it had 1MiB of core memory and 2MiB of LCS (slow core
>> memory).  It ran most of the computing work for the whole campus,
>> including student programs.
>>
>> The successor to this hardware is IBM's System Z.  The latest announced
>> processor chip has 512MiB of cache per socket.  I have no idea how many
>> sockets a large system would have.
> 
> Well they claim up to 190 user configurable cores (no idea how many
> total cores that means given some are reserved for the system I guess).
> At 5.2GHz.  They don't make it easy to understand.
> 
> Looks like up to 5 drawers, with up 4 sockets each, and 12 cores with
> 2 threads, so 48 cores per drawer but only 41 or 43 active in a drawer,
> and clearly not all available for the customer to use.  And then 8TB
> effective ram per drawer (using 10TB actual ram in some kind of "RAID"
> they call "RAIM").  All fit in 4 racks, which is rather tiny compared
> to the old machines.
> 
>> The /360 architecture only allowed for 24 bits of address -- 16M.  The
>> /370 eventually allowed for 31 bits of address.  I don't know what Z's
>> limits are.  Anyway, the whole contents of the 360-75 core would occupy
>> 1/512 of the cache of one socket of the Z.
> 
> I believe all z series have been 64 bit address space.
> 
>> The -75 didn't even have a cache.  The -85, introduced a couple of years
>> later, did.  When an Ottawa company (SDL?) got one, that became the
>> largest computer in Canada.
>>
>> The fastest instructions on the 360-75 (for example, adding two registers)
>> took .39 microseconds.
>>
>> On my main computer in those days, the IBM 1710 Model 2, the fastest
>> instruction took 70ns, plus 10ns for each pair of digits processed.  The
>> -75 was a LOT faster.
>>
>> Now ordinary PCs are 2GHz or more and execute better than 1 instruction
>> per cycle.  Perhaps 1000 times faster than the 360-75.
>>
>> Bulk RAM is perhaps only 10 times faster.  But cache has a large effect.
>>
>> Disk latencies might not be a lot better: 2,400 RPM vs 10,000 RPM but seek
>> times, capacity, and bandwidth are.  Not to mention SSDs.
>>
>> I cannot even estimate power requirements.  And you have to add power for
>> cooling.
>>
>> The price is perhaps 10,000 times lower.
>>
>> You can see why I'm not really impressed with x86 improvements since
>> Haswell.
> 
> Oh intel has been slacking off lately.
> 

Sure and considering AMD seems to be going to 5nm. Alongside, doing 128cores/256 threads:
https://www.tweaktown.com/news/80337/amd-epyc-bergamo-cpus-zen-4-128-cores-256-threads-on-5nm-tsmc/index.html

The article is a little old  but this is what seems to be predicted for Zen4 in the enterprise.

Nick