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Historical price charts for RAM are quite readily available, e.g. in the mid-seventies a ballpark figure was a penny a byte. What was the price of ROM (assuming you were getting the chips produced in quantities at least a few thousand) in that time period? I imagine it was cheaper than RAM, but by how much? (Every Google search hit I find, assumes I'm misusing ROM to mean anything from flash memory to magnetic tapes, which is a weirdly rapid timescale for a term to decay.)

rwallace
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    I don't know the answer to your question, but you might try searching for EPROM (or EEPROM). That search term is less likely to have decayed. – Greg Hewgill Jan 16 '17 at 22:31
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    @GregHewgill Judging from the question I think he's more interested in the cost of masked ROMs (pre-programmed, non-erasable) which would be significantly cheaper than EPROMs at the time. – mnem Jan 16 '17 at 22:53
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    When comparing prices, keep in mind that most RAM price for that time was for dynamic RAM, something that cannot operate without further circuitry for refresh. SRAM was ridiculously more expensive than today, in comparison. – tofro Jan 16 '17 at 23:15
  • Here's a table with some price comparisons over time, but seems to be RAM only: http://www.jcmit.com/memoryprice.htm – tofro Jan 16 '17 at 23:20
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    I have a Computerworld 10/1977 here: It says 2:1. Might be on Google Books. – tofro Jan 16 '17 at 23:24
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    I am interested in the cost of masked ROMs. Following Greg's suggestion, I did find a document saying masked ROMs are 3 to 5 times cheaper than EPROM, but nothing saying how the price of EPROM compared to RAM. – rwallace Jan 16 '17 at 23:27
  • Masked ROMs are essentially ASICs, and as such the cost is going to track roughly with that of chip fab and NRE. ROMs that don't hold large amounts of data didn't have to be physically large, which nets a higher per-wafer yield than EPROMs sold in standard-sized increments like 2K. Actual numbers will be difficult to find unless you can connect up with someone at a chip maker that's willing to dig it up and give it to you. – Blrfl Jan 17 '17 at 18:08
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    The term you are looking for is "mask ROM" resp "masked ROM". No ambiguity there. – rackandboneman Feb 19 '18 at 16:55
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    @Blrfl: I would expect that when fabricating a mask ROM, all but one of the films would be completely standard. Further, since mask ROM chips with a given capacity will have the same layout regardless of content, it should be practical for a company to combine multiple different patterns on each wafer. If a wafer can hold 200 dies, and 8 customers each want about 1000 chips with a particular pattern, a company could shoot one film with 25 copies of each pattern and then use it to make 40 wafers, test every die thereon, and then separate out the chips. Much cheaper than doing 8 custom chips. – supercat Feb 21 '18 at 19:17
  • What kind of ROM? Surplus uniselectors were probably pretty cheap. (My point, of course, is that retrocomputing encompasses much more than microprocessor-era components) – dave Jan 01 '21 at 21:33

4 Answers4

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You can get a sampling of prices for EPROMs the hard way, by checking ads from electronics magazine archives. For example on page 116 of Popular Electronics Jan. 1977 you can see the 1702A 2K(bit) EPROM listed for $12.95. The old magazines always had full-page ads with components near the end.

Mark Ransom
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We can infer the price of one of the first ROM reading the agreement signed between the Japanese Nippon Calculating Machine (later Busicom) and Intel in February 1970 (available here). The agreement provided for manufacturing of a set of 4 chips: RAM, ROM, shift register, CPU (this was the famous Intel 4004, made by Federico Faggin). ROMs cost consisted of a fixed part and a variable part. Fixed part was:

  • $60k as development charge of the 4 chips. The breakdown of this cost is: about $15k for RAM, $10k for ROM, $5k for shift register, $30k for CPU
  • $2k ‘as the tooling charge for each ROM separately’. NCM undertook to purchase 60k kits of the chips with the cost dropping with volume: The first 50,000 ROMs cost $13 each with each additional ROM costing $12. The cost per bit can be found recalling that the ROM stored 256 8-bit words, i.e. 2048 bits.
Alex Hajnal
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Angelo Gallippi
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From The Textbook of Video Game Logic p. 93, a 16 kilobit ROM would cost about $15 when the book was printed in 1976. I assume this is in quantities of 5000+ or so.

8bitworkshop
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Another interesting price in january 1980 page 103 :

CM6571 128 X 9 X 7 ASCII Shifted with Greek $13.50 It was a preburn ROM, so it's the scale of price of a 8 kilobit ROM. So, if you were a game maker, you could imagine the price of you preburn ROM.

Ontologiae
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