ps2...@yahoo.com (Ed Gould) writes:
> Rick:
> I do not remember the maker (this was probably 30 years ago) we had a
> Solid state device and we used it for two things. One was PLPA and the
> other was for a high activity dataset that an application "needed". We
> fought with the application people for several years to redesign
> it. We finally convinced them (after a *LOT* of political cr*p) to use
> VIO. That small change decreased run time from 4+ hours to less than 1
> hour.
>
> We also had issue with it when ever there was a power glitch it took a
> double IPL (delete/define the PLPA). Management finally said the
> change over to VIO was all that was needed and they kicked the vendor
> out. When it worked it worked fine when it didn't it crippled the
> system.

late 70s, early 80s ... internally there was a lot of "1655" from a
vendor ... used for paging at large number of internal vm370 sites.
they could be configured as 2305 fixed-head disk emulation or as native
(if you wrote the support).

the vendor was maker of dram chips ... and the story was that the chips
used in 1655 had failed processor memory acceptance tests. the
characteristic of block i/o to/from 1655 allowed the i/o controller to
compensate for some number of operational characteristics that wouldn't
have been acceptable in processor memory.

at that time ... i had also wanted to add separate exposure to the 3350
fixed-head feature (so i could do transfer from fixed head area
overlapped with 3350 disk arm motion) ... I got shutdown by POK
"JUPITER" effort that was planning on doing something similar to 1655
(JUPITER thot they were going after the paging device market and decided
my alternate exposure for 3350 fixed-head feature would impact their
sales). JUPITER then found out that the corporation didn't have any
spare memory chips for use in emulated i/o device (especially when price
as processor memory was much higher than could be gotten for emulated
paging device). Eventually JUPITER effort threw in the towel ... but not
before shutting me down for ever doing alternate exposure for 3350
fixed-head feature.

Eventually there was Ironwood/Sheriff (3880-11 & 3880-13); 8mbyte disk
controller cache ... Ironwood was 4k byte record cache ... and Sheriff
was full-track cache.

Some of this changed with 3090 and extended store ... but until then
... lots of systems were becoming more & more real storage constrained
(especially MVS systems) and 370 had trouble supporting more than
16mbyte real storage (except for the hack introduced for 3033 that
fiddled two bits in the page table entry to get 26-bit real storage
addressing).

some past posts mentioning the 370 >16mbyte hack
http://www.garlic.com/~lynn/93.html#14 S/360 addressing
http://www.garlic.com/~lynn/2001b.html#69 Z/90, S/390, 370/ESA (slightly off 
topic)
http://www.garlic.com/~lynn/2001i.html#13 GETMAIN R/RU (was: An IEABRC 
Adventure)
http://www.garlic.com/~lynn/2002c.html#40 using >=4GB of memory on a 32-bit 
processor
http://www.garlic.com/~lynn/2003d.html#26 Antiquity of Byte-Word addressing?
http://www.garlic.com/~lynn/2003g.html#24 UltraSPARC-IIIi
http://www.garlic.com/~lynn/2004.html#0 comp.arch classic: the 10-bit byte
http://www.garlic.com/~lynn/2004.html#17 Holee shit!  30 years ago!
http://www.garlic.com/~lynn/2004c.html#6 If the x86 ISA could be redone
http://www.garlic.com/~lynn/2004n.html#50 Integer types for 128-bit addressing
http://www.garlic.com/~lynn/2004o.html#57 Integer types for 128-bit addressing
http://www.garlic.com/~lynn/2005.html#34 increasing addressable memory via 
paged memory?
http://www.garlic.com/~lynn/2005p.html#1 Intel engineer discusses their 
dual-core design
http://www.garlic.com/~lynn/2005p.html#19 address space
http://www.garlic.com/~lynn/2006p.html#0 DASD Response Time (on antique 3390?)
http://www.garlic.com/~lynn/2007o.html#10 IBM 8000 series
http://www.garlic.com/~lynn/2007o.html#56 360/30 memory
http://www.garlic.com/~lynn/2008f.html#12 
Fantasy-Land_Hierarchal_NUMA_Memory-Model_on_Vertical
http://www.garlic.com/~lynn/2010.html#84 locate mode, was Happy DEC-10 Day

-- 
42yrs virtualization experience (since Jan68), online at home since Mar1970

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