Re: Apple IIgs Hard Drive

[Rich <rich@dreher.NOSPAM.net>]

In article <MPG.1b73102e858595e989685@news.uregina.ca>, 
Carlno.spamplezeReilly@uregina.ca says...
> Am I correct in saying that only 2G (+128MB) is all that can be used 
> with GS/OS installed?  Leaving the the other 7G's or so of a 10GB HD 
> wasting?  2G is a tremendious amount of space for this beast, that's for 
> sure.  I read the user's guide this morning and was a little confused 
> between pg's 18 and 10.  I'm not thoroughly aware of the limits of 
> ProDOS or the GS/OS.  Out of curiousity, are there any other OS's for 
> this beast?  I am aware of GEOS, but haven't really heard anything about 
> it on the Apple side of things.
> 


Hi Carl, et al.

I just wanted to follow up to be sure there was no confusion about
the CFFA. The bit about formatting in slot 5 only pertains to ProDOS,  
when formatting drives > 2. If you are using GS/OS to format those 
partitions, there is no problem and it can be done in any slot.
Really the problem is a bug (found by Dave Lyons) in Copy ][+ and Apple 
Sys Utils, with the way it calculates the drive size for partition 
mapped to other slots using smartport. Slot 5 doesn't suffer this 
problem because it supports 4 drives using a different method than the 
other slots do.
Another solution would be to use a format tool that doesn't have the bug
and could therefore be used in any slot. Davex utilities come to mind 
here.

About the maximum drive size that the CFFA supports, yes, it is 2 GB 
under GS/OS and 256MB under ProDOS (8 drive setting). I confess, I have
never tried getting 2 GB to work under GS/OS.
The 2GB limit, was chosen somewhat arbitrarily by myself and Dave 
Lyons' (Davex creator). It was chosen because as the drive size 
increases, GS/OS is forced to work with larger and larger chunks of 
data. What micro$oft would call the "cluster" size. Under GS/OS the 
entire partition is divided into 65536 clusters. The "cluster" is the 
_smallest_ block of data that GS/OS can read or write at a single 
access. So if you wanted to access a 10GB drive as one partition, it 
would require GS/OS to access 163840 (160KB) bytes of data to read a 1 
byte file. So, imagine your IIgs, reading and writting 160K
chunks of data on every access.  I can only guess that things would slow
down considerably.
But note that the CFFA hardware itself, with a GS/OS driver modification 
or firmware modification, should be able to access up to 128GB of data.
Of course, 1 cluster whould be 2MB in that case! No such modifications 
are planned by me, but maybe someone else could try it.

Thanks,
Rich
http://dreher.net/CFforAppleII/