UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - What was your first computer and do you still have it?

From_Australia · 7th Sep 2008, 6:25 am

Hi, my 1st computer was a SC/MP (Simple Cost-effective MicroProcessor) by National Semiconductor which I had purchased in 1976. It has 512 bytes of ROM and 256 bytes of RAM and was connected via a current loop to a mechanical ASR33 Teletypewriter which was the console to operate the SC/MP computer. It was a kit that had to be assembled. I wrote a Random Morse Code Practice program to fit into 252 bytes of RAM, 4 bytes of the 256 byte RAM was used by the KITBUG operating system. I had one byte of RAM left over. The KITBUG operating system was programmed into the 512 bytes of ROM. To load a program into the SC/MP computer you had to type in each machine code instruction via the K/Board or via the paper tape reader that was on the ASR33 Teletypewriter console.

The following URL shows a later version which didn't need the expensive ASR33 Teletypewriter.

http://www.old-computers.com/museum/...sp?st=1&c=1147

I still have the SC/MP with the original user manuals etc and a copy of the Random Morse Code Practice Program. But I no longer have the ASR33 Teletypewriter.

Regards,

Roderick Wall.

7th Sep 2008, 6:25 am	#107
From_Australia Retired Dormant Member Join Date: Sep 2008 Location: Melbourne Australia Posts: 2	Re: what was your first computer and do you still have it? Hi, my 1st computer was a SC/MP (Simple Cost-effective MicroProcessor) by National Semiconductor which I had purchased in 1976. It has 512 bytes of ROM and 256 bytes of RAM and was connected via a current loop to a mechanical ASR33 Teletypewriter which was the console to operate the SC/MP computer. It was a kit that had to be assembled. I wrote a Random Morse Code Practice program to fit into 252 bytes of RAM, 4 bytes of the 256 byte RAM was used by the KITBUG operating system. I had one byte of RAM left over. The KITBUG operating system was programmed into the 512 bytes of ROM. To load a program into the SC/MP computer you had to type in each machine code instruction via the K/Board or via the paper tape reader that was on the ASR33 Teletypewriter console. The following URL shows a later version which didn't need the expensive ASR33 Teletypewriter. http://www.old-computers.com/museum/...sp?st=1&c=1147 I still have the SC/MP with the original user manuals etc and a copy of the Random Morse Code Practice Program. But I no longer have the ASR33 Teletypewriter. Regards, Roderick Wall.