Help me understand memory IC's memory organization.

[MarkS]

I'm coming from the software side, where a megabyte of available RAM is a megabyte of available RAM. When I look at memory IC's, however, it gets all weird. For instance, a 64Kx8 SRAM has 65536 8-bit bytes, but a 64Kx16 has 131,072 8-bit bytes or 65536 16-bit words? Or to put it another way, a 64Kx8 has 64K of memory, but a 64Kx16 has 128K? Is this correct?

[pqass]

Or to put it another way, a 64Kx8 has 64K of memory, but a 64Kx16 has 128K? Is this correct?

Yes.
And when you look at the datasheet for a particular SRAM chip you'll see size in {kilo|mega}bits and then its organization (eg. 128K x 8  or 64 x 16).

[MarkS]

Or to put it another way, a 64Kx8 has 64K of memory, but a 64Kx16 has 128K? Is this correct?

Yes.
And when you look at the datasheet for a particular SRAM chip you'll see size in {kilo|mega}bits and then its organization (eg. 128K x 8  or 64 x 16).

Thank you. The thought that if I want 32K of RAM in a retro computer with a 16-bit data bus, as an example, I would need one 16Kx16 or two 16Kx8 chips just kind of breaks my brain a bit. I get it now, but my eye still twitches at the though that one "16K" chip = 32K!

[CaptDon]

For the longest time since the evolution of 8 bit computers we still think in terms of 8 bit bytes. Also, for the longest time I.C. packages couldn't support more than 8 bits due to pin count. Memory had 24, 28, 32 and later more pins. Remember, you need 8 for data, probably 4 or 5 more for control and many more for the address lines. Now we commonly find BGA packages with 144 pins or more. 8 bit memory chips are still probably at least 50% of the marketplace so for 16 bit wide memory you generally need at least 2 memory packages.

[tooki]

Or to put it another way, a 64Kx8 has 64K of memory, but a 64Kx16 has 128K? Is this correct?

Yes.
And when you look at the datasheet for a particular SRAM chip you'll see size in {kilo|mega}bits and then its organization (eg. 128K x 8  or 64 x 16).

Thank you. The thought that if I want 32K of RAM in a retro computer with a 16-bit data bus, as an example, I would need one 16Kx16 or two 16Kx8 chips just kind of breaks my brain a bit. I get it now, but my eye still twitches at the though that one "16K" chip = 32K!

The “16K” causing you fits should not be looked at as “kilobytes”, but as “number of rows” or similar. It is part of the larger term (e.g. 16Kx16) that describes the structure, not (just) the size.