[GreenKeys] Question: Suppose There Were No Computers Or Glass Monitors...

[Harold Hallikainen]

On Sun, March 6, 2022 7:35 pm, Christian Gauger-Cosgrove wrote:
> On Sun, 6 Mar 2022 at 13:19, Jordan Spencer Cunningham <js at teletype.net>
> wrote:
>> I envision in this fantasy world of mine that paper tape would have
>> still largely given way to magnetic tape, even magnetic cassette tapes
>> that could be popped in and out of any teleprinter or other
>> data-processing machine for quick sneakernet data sharing. There would
>> probably be some alternative media types like magnetic hard disks and
>> floppy disks and the like, but magnetic cassettes would be the main type
>> of exchangeable data storage.
>>
> Ever heard of DECtape/LINCtape and the successor, DECtape II?
>
> It's magnetic tape. That acts like a (very slow) disk. The latter even
> runs over a standard serial port. (You can use a modern machine to
> emulate a DECtape II drive for machines that use it.)
>
> Best regards,
> Christian
> --
> Christian M. Gauger-Cosgrove
> STCKON08DS0
> Contact information available upon request.

When I built my first computer (wire wrapped MC6802 system), I used the
XR2206 and XR2211 to save and load programs using the Kansas City Standard
( https://en.wikipedia.org/wiki/Kansas_City_standard ). I bought a
cassette with integer Basic from Southwest Technical Products. Later, I
licensed Basic from Microsoft (
https://bh.hallikainen.org/uploads/harold/MsLicense801210.pdf ). I
experimented with the Stringy Floppy (
https://en.wikipedia.org/wiki/Exatron_Stringy_Floppy ) for program
storage. I used an encoding system similar to bar codes. The amount of
time between transitions was varied with one time representing a mark and
a different time representing a space. The averages of the mark and space
times were kept to determine the mark/space threshold time with varying
tape speed. Finally, I ended up using the Commodore 1541 for program
storage. See Disk Program Storage at
https://bh.hallikainen.org/uploads/HfDrc190.pdf#page=109 .

Data storage is a fun topic! One of the more interesting (to me) tricks
where I needed a way to load new firmware into a microcontroller was to
put the new firmware on a freshly formatted SD card. The boot section of
the microcontroller flash did not have enough room to put a full SD card
file system. So, the freshly formatted SD card had one file on it. It was
a copyright notice followed by Intel hex of the application code to be
loaded. If a firmware update was triggered (hold down a couple buttons on
power up), an SPI interface to the SD card was initialized, then the card
was read byte by byte starting in the first sector. This continued until
the copyright notice was found, then the Intel hex was read and the
application area of the flash in the microcontroller was programmed.

Fun stuff!

Harold
https://w6iwi.org



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