re: Gnat-Mac and Disk space

[emery@grebyn.com (David Emery)]

In article <1996Apr19.112413.53772@nova.wright.edu>,
jmatthews@nova.wright.edu (John B. Matthews) wrote:

...
> MacTen (out of the box) + gnat for Mac (off the net) takes up
> 47,671,668 bytes for 2968 files. That's 51 MB in a 94 MB partition
> but about 120 MB in a 1 GB partition.
> 
> Hope this helps.
> 
> John
> ----------------------------------------------------------------
> Dr. John B. Matthews
> jmathews@nova.wright.edu; john_matthews@ccmail.dayton.saic.com
> "Whom the gods would destroy, they first invite to program in C"

It's a real quirk of the MacOS file system that the minimum amount
of disk space used by a small file is a function of the size of the
file system/partition.  Apparently MacOS divides the disk into 1/N 
parts, where N is CONSTANT.  Thus, a 1GB disk drive (single partition)
will use 4 times as much space for a 10-byte file as a 250mb file
partition.  

The solution to this is to use disk driver software that partitions
the drive.  I'm currently using 135mb partitions (with a "double partition"
for all my Mac applications) on a 1GB drive.  (I use Silverlining for
disk driver/partitioning, but most good disk driver packages for the
Mac support multiple partitions.)  (I selected 135mb as the size of
a EZ135 cartridge, should I ever buy one, I know that I can completely
backup/restore a file system (without fancy backup programs) to a single
removable disk.  

Not only will partitioning save you disk space (particularly for things
like GNAT, which uses lots of very small files), it also improves disk
performance, etc.  

And, last but not least, you can install various OS on different partitions.
I'm currently running MacOS 7.5.1 on one partition, and 7.5.3 on another.
When my copy of MachTen arrives (hopefully next week :-), I'll install it
on a separate partition.

            dave