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Did the MITS Altair 4K Board Not Work Back In The Day?

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Pentad4k

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I've been reading books on the early days of the computer market and many stated the MITS Altair 4k board did not work reliably. Unfortunately, none of them have detailed what that meant. I was wondering if anyone here could explain if there was an issue with MITS 4k board, what it would do (or not do), and if MITS ever solved it? I believe Fire in the Valley said many 3rd party companies released 4k boards that did work so Microsoft Basic would have more memory to use. I think they referenced Memco(sp?) as the first 3rd party 4k board?

Thank you for sharing any information and experience you might have had during this time! :)
 
My understanding was the early 4K board (the DRAM model) was not well designed and was prone to losing bits during refresh cycles and bus resets.
The SRAM board didn't have this problem because it didn't require constant refresh cycles. (Static Ram)
 
NeXT,

Thanks for the information! I never realized that there were both dram and sram, but I can see why the sram board would have less issues. Do you know, was there a price difference between the sram and dram versions?

Thanks!
 
Pentad4k said:
...many 3rd party companies released 4k boards that did work so Microsoft Basic would have more memory to use.
Click to expand...
Make that any memory to use. "4K" MS-BASIC left only about 600-odd bytes free for your program, IIRC, and that's only if you didn't load the trig functions.
 
My 8800 was supplied with 2 4K board kits. The DRAMs were the TI clone of the Intel 2107 22 pin (0.4" width) ICs.
Hit reset a bit too long and your data was corrupted. Oh, how I hated those things! I replaced them with a couple of 8K boards using 91L02 SRAMs and my problems went away.
 
Pentad4k said:
NeXT,

...was there a price difference between the sram and dram versions?

Thanks!
Click to expand...
Yes, there was a significant price difference. The MITS price in early 1975 for the assembled version of these boards was $338 for the 4K DRAM board and $209 for the 1K SRAM board. At that point in time, a 4K SRAM board was not available.
 
Thank you all for the information! I never knew the prices of the hardware and the issues involved. I also never thought about how much memory was left after MS Basic was loaded until CJS pointed out that only ~600 bytes was left. No wonder people had multiple memory cards!
 
Manes' biography of Gates has some good details about the MITS DRAM boards and MITS economics at the time (chapters 5 and 6). The RAM cards were an important money maker for MITS, and the flakiness of the boards contributed to a lot of resentment among customers (including not paying for BASIC according to some). Roberts argued that DRAM was necessary for power efficiency compared to SRAM (the original Altair PSU being somewhat light, p. 85). Meanwhile, Processor Tech, Godbout, and others, were eating MITS lunch selling 4K and 8K static boards.
 
Chuck(G) said:
At least one of my 8K boards is from SSM. Basically 64 1Kx1 SRAMs of the 2102 persuasion.
Click to expand...
I have SSM, Vector Graphic, and Duston 8K boards in my IMSAI. Lots of 2102s. Those last two are notable because they show up in Ward Christensen and Randy Suess's article about their first BBS in Byte Vol 3, #11, 1978. They note the additional memory they purchased: "We are now running an 8 K Vector Graphic memory board and two 8 K byte boards designed by Forrest Duston (a local hobbyist and design engineer), which were donated by Lloyd Smith and Bill Bassett of DMA Inc."
 
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