On a sunny day (Sat, 7 Mar 2020 10:00:23 -0000 (UTC)) it happened Martin
Gregorie  wrote in :

>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!

OK, I did, apple juice is nice, no nothing to do with ipads... ;-)


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.

Yes, thinking about the dates, if memory serves me well...
in the eighties I worked as electronic designer for a company basically across
the road from IBM,
designing among other things ISA cards for in the PC, we did very large
projects for industry.



>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.

There is a history, in around 1968 to 1976 I worked as technician for the
national broadcasting
network here, bit like BBC in the UK.
In the 1975? or so we had slow motion machines that used BIG disks, the Ampex
HS100,
it had 4 heads on 2 disks, one head recording one head playing back the same
time,
changing and cleaning platters had to be done on occasion:
 https://www.youtube.com/watch?v=cW7jvmoLQ7o
I worked with all sorts of Ampex recorders, from the old tube types to the
AVR1,
even went weeks to Germany for training on the electronics, quite complicated.




>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.

6502 .. Motorola max board, commodore PET
 https://en.wikipedia.org/wiki/Commodore_PET
  remember playing moon landing game on that at work in 1979...
  worked at a large accelerator then...
Designed and build my first video digitizer in those days, predicted video over
phone lines....
Wild times!!!

bit later I bought a ZX80 for myself and had a go, then a ZX81, wrote a CP/M
clone for ZX81
added all sort of cards, created floppy interface, so it finally could run CP/M
programs.
had a C compiler too (Software Toolworks),
 http://panteltje.com/panteltje/z80/system14/index.html

This is what the later ZX81 turned into:
 http://panteltje.com/panteltje/z80/system14/diagrams/index.html

When on some assignment later I designed my own processor.. CMOS
a whole 19 inch rack full of eurocards.

The plus of this is I learned to get maximum out of the resources.

There is more... first encounter with Unix in 1979,
had a nice Unix book too back then, when I came across Linux in 1998
I just grabbed that book and was flying.

No bloat ..... asm is cool, directly talk to the hardware, that is why I like
PIC micro controllers
always program those in asm.
Microwatt power consumption, few bytes of RAM and FLASH, you can do anything:
 http://panteltje.com/panteltje/quadcopter/index.html

Carried away here..

programming is simple
one thing though:
Programming is like giving instructions on a map where to go to somebody.
first left, second right, over the bridge third right.
ONE mistake and the rest makes no sense and leads anywhere but usually not
where you want to go.
And you can ONLY give those instructions if you KNOW the way.
People seem to think these days that t computers will know the way..
and there the chaos and bloat and all the failed IT projects start,
Computers know nothing, programming is just using some language
like giving instruction in Spanish or German or English or Dutch or French,
you STILL need to know the way,
 Dunno about IT these days but it seems to me people do not quite understand
that
So you have to be
1) expert in at least some language (to be able to tell the hardware what to
do)
2) Know the field you are programming for.

You cannot program for financial markets if you are not good at that stuff,
any other subject the same.
So for any new project you may need to start from scratch and start a new
study.

Its fun, a life long study of ever new subjects if you want,
I like to use things I learned in one filed and ply it to the other.
But those things like learn programming in 2 weeks make little sense to me,
also because at the basis is the hardware, and people should start there,
I started coding in binary.

Still on topic for this group? Maybe yes, but time....
how many years should some men
 https://www.youtube.com/watch?v=vWwgrjjIMXA

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