Storage Virtualization

Anne & Lynn Wheeler

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Mar 12, 2002, 12:23:15 PM3/12/02

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an earlier virtual disk (1974) was 3850 Mass Storage System and all
those honeycomb tape cartridges that virtualized 3330 disk drives from
the early '70s if i remember correctly, 3850 had two staging
option/mode ... one was full-tape ... aka half (50mbyte) a 3330-I
(100mbyte) drive ... and the other was six(?) 3330-track
increments. The following mentions supporting 3350s (317mbyte), but I
don't remember if there was also any support for (full) 3330-II
(200mbyte drive). 3850 had tape robot ... but it wasn't an automated
tape library, it was a virtual disk system.

There was lore about speed of the tape robot and situation where
somebody entered the 3850 interior and the robot going into
motion. After that there was in interlock placed on robot operation
whenever the access door was opened.

there was ironwood, 3880-11 disk controller cache in the very early
'80s (4k block though) ... and then '83 sheriff, 3880-13 full-track
disk controller cache.

from:
http://www.beagle-ears.com/lars/engineer/comphist/ibm_nos.htm

3850
Mass Storage System (1974 to 1990)

A robotic tape storage system, featuring tape cartridges about the
size and shape of a 12- ounce soda drink can, containing a wide strip
of tape wound on a spool.

The cartridges were stored in two facing walls of honeycomb-arranged
slots. Mechanical pickers (one or two, depending on the 3850 model)
went back and forth between the storage walls, moved vertically and
pivoted to reach the desired slot, then pulled a cartridge and carried
it to one of multiple tape drive stations. At the drive, the cartridge
cover was removed and the tape was read or written using helical-scan
heads like those on a 4mm or 8mm digital tape drive. Each cartridge
held about 50MB, a 3330 drive image filled two cartridges.

There were dedicated 3330 disk drives onto which data was staged from
cartridges. Once staged, the data was accessed from the 370 mainframe
like ordinary disk data. The entry- level 3850 had a total storage
capacity of 35GB, but a fully-expanded system could hold much more (up
to 472 GB). After the 3330 DASD went out of fashion, 3830 MSS systems
were fitted with 3350 drives, but the 3830 code was never updated to
use the additional capacity of the newer drives.

Pictures at http://www.coulmbia.edu/acis/history/mss.htm

.......

"Jean Dion" <jean...@videotron.ca> writes:

> You forgot the inventor of Virtual disk storage and disk Virtual Snapshot
> back in 1994...StorageTek code name Iceberg and now V960. They were sold as
> IBM RVA (Ramac Virtual Array) for few years (1995-1999).
>
> Here is some StorageTek industry first to storage:
>
> - 1978 Solid State Disk (SSD). Memory emulating disk.
> - 1986 Disk controller cache
> - 1987 Automated tape library with more than 96000 cells.
> - 1994 Virtual Disk and world first disk Snapshot without twice the storage
> requirement.
> - 1998 Virtual Tape (IBM mainframe)
> - 2001 Virtual SAN with SN6000
>
> You have also Compaq (HG80 controller), HP (V7400) and Xiotech also have
> true virtual storage subsystems.
>
> To get more on virtual take a look at www.infostor.com
>
> Jean Dion Tools & Programs
> http://pages.infinit.net/dbtek/

--
Anne & Lynn Wheeler | ly...@garlic.com - http://www.garlic.com/~lynn/

Daniel House

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Mar 12, 2002, 5:17:27 PM3/12/02

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"Anne & Lynn Wheeler" <ly...@garlic.com> wrote in message
news:uit816...@earthlink.net...

>
> an earlier virtual disk (1974) was 3850 Mass Storage System and all
> those honeycomb tape cartridges that virtualized 3330 disk drives from
> the early '70s if i remember correctly, 3850 had two staging
> option/mode ... one was full-tape ... aka half (50mbyte) a 3330-I
> (100mbyte) drive ... and the other was six(?) 3330-track
> increments. The following mentions supporting 3350s (317mbyte), but I
> don't remember if there was also any support for (full) 3330-II
> (200mbyte drive). 3850 had tape robot ... but it wasn't an automated
> tape library, it was a virtual disk system.
>
> There was lore about speed of the tape robot and situation where
> somebody entered the 3850 interior and the robot going into
> motion. After that there was in interlock placed on robot operation
> whenever the access door was opened.
>

There was also lore that I heard in 1980 from testers who worked on the
MSS/3850 that an early model was acting up with a particular test case. It
would "lose" a cartridge. Someone had to look inside while it ran to see
that the little robot grabber was dropping the cartridge. It rolled into a
hole and under the raised floor. Can't verify accuracy, but it was funny at
the time.

Regards,
Dan House

Jean Dion

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Mar 12, 2002, 7:17:21 PM3/12/02

to

This was more an HSM hardware application than virtual disk. Files were
"moved" to tape and back to disk like any HSM application does today.

I used to work around some of those Masstorage back in 1982. My customer
used to have one and they were very happy to get it out. It was out of
order every day for few hours. IBM CE was happy too!

Todays virtual disk are "not" moving files to tape but spread the files
within the disk subsystem to get better disk usage and features like
snapshot.

Jean Dion Tools & Programs
http://pages.infinit.net/dbtek/

"Daniel House" <d.h...@computer.org> wrote in message
news:X7vj8.37226$0S4.19...@typhoon.southeast.rr.com...

Douglas H. Quebbeman

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Mar 13, 2002, 7:24:50 AM3/13/02

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"Anne & Lynn Wheeler" <ly...@garlic.com> wrote in message
news:uit816...@earthlink.net...
>

> Pictures at http://www.coulmbia.edu/acis/history/mss.htm

Link rot hath claimed yet another victim...

:(

Daniel House

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Mar 13, 2002, 5:32:11 PM3/13/02

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"Douglas H. Quebbeman" <dqueb...@acm.org> wrote in message
news:3c8f4...@news.iglou.com...

Finger rot. It's slightly mispelled:

http://www.columbia.edu/acis/history/mss.html

It's more entertaining to start here:

http://www.columbia.edu/acis/history/

Regards,
Dan House

Douglas H. Quebbeman

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Mar 16, 2002, 9:43:35 AM3/16/02

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"Daniel House" <d.h...@computer.org> wrote in message

news:LrQj8.38174$0S4.20...@typhoon.southeast.rr.com...

>
> "Douglas H. Quebbeman" <dqueb...@acm.org> wrote in message
> news:3c8f4...@news.iglou.com...
> > "Anne & Lynn Wheeler" <ly...@garlic.com> wrote in message
> > news:uit816...@earthlink.net...
> > >
> > > Pictures at http://www.coulmbia.edu/acis/history/mss.htm
> >
> > Link rot hath claimed yet another victim...
> >
> > :(
> >
>
> Finger rot. It's slightly mispelled:

The arthur itis is starting to take hold here, too...

-dq

Rostyslaw J. Lewyckyj

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Mar 23, 2002, 3:29:45 AM3/23/02

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"Jean Dion" <jean...@videotron.ca> writes:

> > You forgot the inventor of Virtual disk storage and disk Virtual Snapshot
> > back in 1994...StorageTek code name Iceberg and now V960. They were sold as
> > IBM RVA (Ramac Virtual Array) for few years (1995-1999).
> >
> > Here is some StorageTek industry first to storage:
> >
> > - 1978 Solid State Disk (SSD). Memory emulating disk.

In the early 1970s the Triangle Universities Computing Center
(TUCC) had an IBM 360/75 with 8Meg of extended core storage.
This was configured as two incomplete 2314 or 2311 volumes
using a home grown system called Hyperdisk. This was slightly
before MVT had support for extended core i.e. where one
could request some memory to be allocated in ecs and direct
the loader to put COMMON data out there. I don't remember
but believe that one couldn't execute out of ecs, or perhaps
it was just too slow. main memory was 2ms. ecs was 8ms.
the path between ecs and the main memory was 8double
words wide.
So while SSD may have been the first commercial ram disk,
it wasn't the first one in existance or use.
--Rostyk