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.
>>
>> 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.
>>
>> 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.
>>
>> 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.

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.

Tell that to the young people today and they'll never believe you ...


--
Martin    | martin at
Gregorie  | gregorie dot org

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