Re: Bad Metric ... 1k = 1024 or 1000?

[dempson@actrix.gen.nz (David Empson)]

phoenyx <phoenyx@texas.net> wrote:

>     On my KEGS/Linux system I have a HFS partition setup as 128k which
> works well. Block size is 1k. For 512k (same as 3.5" HFS floppy) you have
> to keep the partition under 96 megs.

Firstly, I think you meant 128 MB instead of "128k", and 512 bytes, not
"512k".

Secondly, to get allocation blocks as small as 512 bytes, you would have
to limit an HFS partition to under 32 MB.

HFS has a maximum of 65535 allocation blocks per volume, and 512 x 65535
is just under 32MB (as we well know from ProDOS).

1 KB allocation blocks would limit you to 64 MB.

1.5 KB allocation blocks gives you up to 96 MB.

2 KB allocation blocks gives you up to 128 MB.

By comparison, HFS Plus (supported by Mac OS 8.1 and later) uses a
32-bit allocation block number, so it can have much smaller allocation
blocks on large volumes.  The default allocation block size is 4 KB
(matching the virtual memory scheme), so HFS Plus wastes less space than
HFS for any volume size over 256 MB.

[This discussion is getting rather off-topic.  Sorry folks.]

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P O Box 27-103, Wellington, New Zealand