On 2020-03-07, Charlie Gibbs  wrote:
> On 2020-03-07, Martin Gregorie  wrote:
>
>> On Sat, 07 Mar 2020 10:31:41 +0000, The Natural Philosopher wrote:
>>
>>> On 07/03/2020 10:00, Martin Gregorie wrote:
>>>
>>>> On Sat, 07 Mar 2020 08:39:47 +0000, Jan Panteltje wrote:
>>>>
>>>>> In the eighties you had IBM drives of maybe it was 10GB? tha thad a
>>>>> mechanical lever likething on the side, it ws connected to teh head
>>>>> movement,
>>>>> If the head positioning got stuck or something you could move that
>>>>> lever and the thing would work again....
>>>>> So, anyways, sorry about that.
>>>>
>>>> Wash your mouth out! Back in the '70s IBM was the Great Satan, with
>>>> predatory salesmen and SEs, all in the dark suit, white shirt and blue
>>>> tie company uniform and many brainwashed to the point of disbelieving
>>>> that anybody other than IBM even made computers. Yes, I did meet, and
>>>> worked with, a guy who had bought (gasp!) 3rd party disk drives and
>>>> consequently had a posse of IBMers show up and harangue his management
>>>> to try and get him fired.
>
> I remember hearing those horror stories.  I worked with Univac gear -
> that company was less organized but friendlier.
>
>>>> Anyway - when I started work with ICL in the late 60s, our biggest
>>>> disks were 8 MB. The drives were desk height, about 50cm X 80cm on top.
>>>> They used removable cartridges with a stack of 10 recording surfaces,
>>>> all 14" diameter. Spun at 2800 rpm and had an average access time of
>>>> around 135 mS.
>
> Sounds like an equivalent of the IBM 2311.
>
>>>> By 1973 they'd grown to 60MB capacity and 20 recording surfaces, still
>>>> using 14" platters, spun a bit faster (3600 rpm IIRC) and access time
>>>> was down a little to under 100 mS. George 3 used a clever head movement
>>>> scheduler that tripled the effective access rate.
>
> Hmmm... double-density 2314?
>
>>>> Biggest drive I ever saw back in the day was 400MB, still using 14"
>>>> removable cartridges, but the number of recording surfaces had more
>>>> than doubled.
>>>>
>>>> FWIW, I first saw a microcomputer in 1976/77 at The Computer Store in
>>>> NYC at 5th and 35th, which sold SWTPC and Imsai systems, No disks of
>>>> any sort - they weren't around much before the early late 70s when
>>>> Shugart 5.25" floppies started to appear and then in the early 80s 5"
>>>> hard drives with (gasp!) 5MB or even 10MB capacity started to appear.
>>>
>>> 8" floppies predated the 5 1/4" for some CP/M style machines
>>
>> Sure - seen 'em but never used them. IIRC an IBM invention - about the
>> only time I can remember seeing them being used was watching an IBM
>> engineer using one to load microcode into an S/38 during the run-up to
>> the LSE Big Bang in the late 1980s.
>>
>>> My first computer had twin 5.25 but IIRC others used 8"
>>
>> Same here - my microcomputer experience started with writing assembler on
>> a NorthStar box with a 6800 MPU. About the same time I briefly used BASIC
>> on an Apple II at the BBC, where I was mainly writing COBOL on ICL 2900
>> mainframes, to simulate how a contacts database for the Radio News people
>> might work.
>>
>> My first computer was a 6809 box with 5.25" floppies, a whole 48KB of RAM
>> and running the FLEX09 OS.
>
> My first home computer was an 8080 CP/M box with 8-inch floppies.  I
> refused to go to 5 1/4-inch floppies because they had no standard format,
> making it a pain in the ass to change data with other users.  (This was
> before the IBM Personal Computer imposed its own standard.)  Our club had
> a Disk Maker, a floppy controller for the S-100 bus; it could handle over
> 400 different 5 1/4-inch disk formats.
>
>> Mind you, the Beeb's pair of 2966 mainframes (respectively production and
>> standby/development) only had 16MB of RAM each, but 'prod' supported
>> around 400 users accessing 11 quite large interactive systems, written in
>> death-defying COBOL with IDMSX databases.
>
> 16MB?  Luxury!  That was the theoretical maximum for the IBM 360.
> I say theoretical because nobody could afford that much in real life.
> Slightly later, into the 370 era, I recall reading in a trade rag
> about how IBM rocked the industry by slashing the price of a megabyte
> of memory from $75,000 to a mere $15,000.  Compare that to your
> $1/gigabyte thumb drives...

Ahhhh, yes.  By the middle 1980s, the 16MB limitation for
individual "virtual machines" was about to be removed.  For a
time, I was the only user of a special EDAC (Extended Data
Address Capability) mainframe from IBM.  The monthly lease for
the machine was $150K, and I was only a couple of years out of
college.  The machine's monthly lease payment was several times
my yearly salary.  Pressure?  What pressure?

--
Robert Riches
spamtrap42@jacob21819.net
(Yes, that is one of my email addresses.)

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