On 03/10/2024 19:56, ben via cctalk wrote:
Not like old computers, that could sing and drives could dance. :)
I know the PDP-8 could do music thru a AM radio. Did they ever have it sing?
No, they used DecTalks.
https://www.youtube.com/watch?v=1l0Ko1GUiSo&pp=ygUecGV0ZXIgbGFuZ3N0b24gZWVkaWUgYW5k
Just curious if you had a known "good" drive, a golden unit so to speak,
that was well aligned with an authentic alignment diskette-- could you
then use that drive to write plain old data diskettes that the downstream
users would then align their drives to?
Could they simply maximize the read si
On Thu, 3 Oct 2024, Jon Elson via cctalk wrote:
Yes, and in a pinch I have done that. What you want is to hack the format
program so you can write just ONE track. Bulk erase the floppy and then
format just one track. Put a scope on the analog read amp signal and see if
it looks good. Then,
On 10/3/24 15:28, Chris Elmquist via cctalk wrote:
Just curious if you had a known "good" drive, a golden unit so to speak,
that was well aligned with an authentic alignment diskette-- could you
then use that drive to write plain old data diskettes that the downstream
users would then align their
On 10/3/24 14:25, Chuck Guzis via cctalk wrote:
On 10/3/24 10:51, Norman Jaffe via cctalk wrote:
The IBM 360 single precision floating point has a range of 10**-79 to 10**75;
double precision and extended precision has the same number of bits for the
exponent.
...and most significanrly, norma
On 10/3/24 10:51, Norman Jaffe via cctalk wrote:
> The IBM 360 single precision floating point has a range of 10**-79 to 10**75;
> double precision and extended precision has the same number of bits for the
> exponent.
...and most significanrly, normalized to only the hex digit (4 bits),
not to
On 10/3/24 10:39, Paul Koning via cctalk wrote:
>
>> On Oct 3, 2024, at 12:01 PM, CAREY SCHUG via cctalk
>> wrote:
>>
>> I worked on a model 1 with 40k memory (my very first computer experience)
>> and floating point, and later a model 2 stripped. I believe the model 2
>> still used table loo
On Thu, 3 Oct 2024, dwight via cctalk wrote:
A small laser interferomenter and a screw driver could be used, once one
determined the center of the track by magnetic material and a microscope. Some
what special equipment but not all that special, now days.
Years ago, I went to a Seagate building
> question: could somebody (did they at the time) write a program for the apple
> ][ to create such a diskette? The apple drive can do half track stepping, and
> IIRC the signal is written strictly by a timing loop in the program
Not really. Merely half-stepping a drive wouldn't be accurate enou
On Thu, 3 Oct 2024 at 02:39, Fred Cisin via cctalk
wrote:
>
> Some of the old-timers might remember a guy who was on this list a long
> time ago, who claimed that the "copy-protectin defeating" program that he
> used could copy ANYTHING, even alignment disks!
> 'course, he was also the one who cla
https://www.bonhams.com/auction/29514/preview-lot/5918785/apple-twiggy-macintosh-prototype-used-in-the-development-of-demonstration-software-macintosh-personal-computer-apple-computers-inc-cupertino-ca-1983-with-5-14-inch-twiggy-disk-drive-with-corresponding-slot-in-front-panel/
APPLE "TWIGGY" MA
> On Oct 2, 2024, at 5:23 PM, Van Snyder via cctalk
> wrote:
>
> On Wed, 2024-10-02 at 16:39 -0400, Paul Koning via cctalk wrote:
>> For the earlier 1311, lack of overlap made perfect sense. After all,
>> the 1620 has no interrupts, no parallelism of any kind: every I/O
>> operation stalls t
The IBM 1710 was a 1620 enhanced for process control. It had interrupts.
Dave Wise
From: Paul Koning via cctalk
Sent: Thursday, October 3, 2024 7:05 AM
To: cctalk@classiccmp.org
Cc: Paul Koning
Subject: [cctalk] Re: Might be antique computer parts
> On Oct 2
A small laser interferomenter and a screw driver could be used, once one
determined the center of the track by magnetic material and a microscope. Some
what special equipment but not all that special, now days.
Years ago, I went to a Seagate building to help a friend with a servo writer
problem.
I worked on a model 1 with 40k memory (my very first computer experience) and
floating point, and later a model 2 stripped. I believe the model 2 still used
table lookup for multiply.
floating point in model 1 (and I think model 2) was limited to a 98 digit
mantissa, still more precision than
On 10/2/24 18:20, Mike Katz wrote:
> It also has off track signals on it. I don't think there is any way to
> create them with anything but a specially modified drive connected to a
> special controller.
Just that--DAD's specifically. We did it with a selected Micropolis
worm-screw positioner dr
> On Oct 3, 2024, at 12:01 PM, CAREY SCHUG via cctalk
> wrote:
>
> I worked on a model 1 with 40k memory (my very first computer experience) and
> floating point, and later a model 2 stripped. I believe the model 2 still
> used table lookup for multiply.
Sure enough, that's what the Model
The IBM 360 single precision floating point has a range of 10**-79 to 10**75;
double precision and extended precision has the same number of bits for the
exponent.
From: "Paul Koning via cctalk"
To: "cctalk"
Cc: "David Wise" , "CAREY SCHUG"
, "Paul Koning"
Sent: Thursday, October 3, 2024
On 2024-10-02 2:52 p.m., bluewater emailtoilet.com via cctalk wrote:
Some PC HD maker offered a drive with a clear top so you could see the heads
moving. I had a friend write a VB program to do random seeks. It was fun to
watch. Still have the drive and the program. Don’t know if the program wi
Some PC HD maker offered a drive with a clear top so you could see the heads
moving. I had a friend write a VB program to do random seeks. It was fun to
watch. Still have the drive and the program. Don’t know if the program will run
in Win 11. 😊
> On Oct 2, 2024, at 13:39, Paul Koning via cctal
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