On Dec 4, 2015, at 9:08 AM, R.S. wrote:
Do you mean 2105 or ESS Shark?
None of them introduced 1024 devs per box.
The relief was intruduced "architecturally" with the ESCON and
implemented in earlier DASD boxes like Ramac RVA (can't remember
model, it was higher than T82), Tetragon 2100 aka HDS Freedom 7700E
and others.
The trick was usage of CUADD - something similar to LPAR from host
side.
ESCON CU supported up to 16 CUADD => 16x256 devices => 4096 devices
per box (some workarounds were possible -- single DASD box can be
defined as more than one CU).
FICON extended it to 256 CUADD => 256x256 => 64k devices which is
the limit for HCD ...unless you define 3390Aliases in SS1 (or SS2...).
--
---------------------SNIP---------------
Back in the 70's (early) we had a limit of somewhere around 1600
(sorry exact number is foggy) devices on MVS.
In our case we were top heavy in the number of 3270's (local). When
IBM introduced the 3274-1A (1 UCB 32 devices) we couldn't migrate
off of the 1D (local 3274's) fast enough. We had to keep some 1D's
for consoles though.
It allowed us to get the 3850 and the scads of DASD that it needed.
Ed
ps: We had hundreds of people doing data entry on he 3270's
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