How to determine size of memory module

[ignotiev]

I'm having trouble finding out how many MB an old memory module contains. The data sheet (which can be found here) says that the ram has "1,048,576 Words x 4 Bit Organization." Does this mean that the module is a gigabyte of ram? I find that hard to believe as it is pretty old (at least 10 years).

Thanks.

 

[Jest3r]

Well, let's see here:

I think a word is 16 bits. So...

1,048,576 / 16 = 65536 bits

65536 * 4 = 262144 bits

262144 bits / 8 = 32768 bytes

32kb memory stick? lol, I know I have to be wrong, but I thought I might try without any real research.

 

[Idontcare]

Originally posted by: Jest3r
Well, let's see here:

I think a word is 16 bits. So...

1,048,576 / 16 = 65536 bits

65536 * 4 = 262144 bits

262144 bits / 8 = 32768 bytes

32kb memory stick? lol, I know I have to be wrong, but I thought I might try without any real research.

you divided by 16 when you should have multiplied.

At any rate its a 4M chip. (word x bit)

 

[ignotiev]

Does that mean it's a 8 MB chip?

 

[daw123]

Following on from Idontcare's post:

1,048,576 x 16 = 16,777,216 bits
16,777,216 * 4 = 67,108,864 bits
67,108,864 bits / 8 =8,388,608 bytes

Therefore an 8M chip.

 

[Idontcare]

Originally posted by: daw123
Following on from Idontcare's post:

1,048,576 x 16 = 16,777,216 bits
16,777,216 * 4 = 67,108,864 bits
67,108,864 bits / 8 =8,388,608 bytes

Therefore an 8M chip.

Yep, not sure how I ended up with 4M...but it's 8M.

The configuration of IC's is bank x word x bit

The OP posted a single-bank IC...so it's just word x bit.

1,048,576 Words x 4 Bit = 1MW x 4bit

(MW = mega-word)

The short-math is MW x bit x 2 = Mb (megabit)

so 1MW x 4bit x 2 = 8 Mb = 1 MB