[net.micro.atari16] Ram disks - Ram Cache?

rb@ccivax.UUCP (rex ballard) (03/01/86)

Does anybody know of a good RAM CACHE program or algorythm?
Asynch read-ahead, and write would be nice, along with demand
based purging.

Such things are available for other machines, and appearantly
save you some of the grief of powering down the ram disk before
you've put it back on floppy.  I've also heard they're real nice
with hard drives.  I know very little about them exept that they
make a machine look like it's running faster.

Is this an OS/Driver hack?

slavenbg@prle2.UUCP (Gert Slavenburg) (03/13/86)

Can anyone tell me what exactly a RAM cache is. I am the person who 
originally made the 520ST RAMdisk, and am thinking about also making a
RAMcache if such proves usefull. However, I have never seen one (though
I can guess a lot) and need some ideas on the functionality.

What I guessed is :
  write through (keep disks updated)
  cache on read miss
  cache on write
  adjustable size cache

What I don't know is :
  do you want it to be completely invisible (no commands)
  how pessimistic should it be about disk exchanges

I can imagine the usefullness of such a tool. However, you still also need
a smaller RAMdisk, since a lot of time goes into write & verify of intermediate
files for C compilers etc. 

Any experience and suggestions please DIRECTLY to me, I'll summarize on the
net.

Gert Slavenburg
..mcvax!prle1!prle2!slavenbg
"mcvax!prle1!prle2!slavenbg"@seismo.ARPA
gert@su-pescadero.ARPA