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pdh

pdh
441 posts

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  #2780029 17-Sep-2021 19:03
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sleemanj:  Sinclair got hold of a load of faulty ram chips cheap, of each chip half the bank was perfectly good, so for a 32k machine they put in 64k of ram

 

 

Um, no. Perhaps you are remembering a different machine.

 

The ZX-81 had 1 KB of RAM and I managed to double it to 2.

 

Wikipedia talks a bit about the challenges with only 1 K - having 2 made things lots easier.

 

They also mention some of the hardware tricks that were played... in the interests of minimalism.

 

I'd forgotten the shenanigans with the video feed.

 

My sister wasn't happy that I kept stealing her cassette recorder either ;-)




allan
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  #2780030 17-Sep-2021 19:06
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CYaBro:

 

RIP :(

 

ZX Spectrum 16k was our first, around 1983, and later upgraded to 48k. 

 

Exactly the same for me. Tucked away in a rumpus room cupboard somewhere. Wonder if it still works?


mugs2000
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  #2780032 17-Sep-2021 19:14
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The ZX80 was my first computer, and with a 4KB expansion pack that I built with some I/O it was able to control m,y Marklin model railway.

 

Later it became a bootloader for a 6809 processor running the FLEX operating system.




sleemanj

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  #2780037 17-Sep-2021 20:12
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pdh:

 

sleemanj:  Sinclair got hold of a load of faulty ram chips cheap, of each chip half the bank was perfectly good, so for a 32k machine they put in 64k of ram

 

 

Um, no. Perhaps you are remembering a different machine.

 

The ZX-81 had 1 KB of RAM and I managed to double it to 2.

 

 

 

 

I was talking about the Sinclair ZX Spectrum

 

https://www.old-computers.com/museum/computer.asp?c=223

 

To keep the prices down Sinclair used faulty 64K chips (internally 2 X 32K). All the chips in the 32K bank of RAM had to have the same half of the 64K chips working. A link was fitted on the pcb in order to choose the first half or the second half.





---
James Sleeman
I sell lots of stuff for electronic enthusiasts...


Tinkerisk
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  #2780090 18-Sep-2021 05:01
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mugs2000:

 

Later it became a bootloader for a 6809 processor running the FLEX operating system.

 

 

HINZVC family? Me 2.  ;-) Motorola EXORSET 30 and the ZX81 with it’s whopping 16kB memory extension. 





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floydbloke
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  #2780119 18-Sep-2021 09:46
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RIP Sir Clive.  Your legacy of making computing affordable for the masses, along with the rampack wobbles, will live on.





Sometimes I use big words I don't always fully understand in an effort to make myself sound more photosynthesis.


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