Hi Kev,
Well, I can not provide any hands-on feedback on the proposed layout (all of my stuff is dumped onto a single drive, this is due to historical reasons as my OS/2 install has gone un-reinstalled since literally the days of the original install, as in Warp3).
However, as applicable to the following hardware configuration of 3 storage drives: SSD 250G, HDD1 280G, HDD2 475G, I will say the following:
1) I do have my main OS/2 partition on the SSD drive, that also has a small 55M maintenance pertition, all of this is mirrored on HDD1
2) leftover space on HDD1 is a 'scratch' area...basically storage dumping ground...LOL, stuff I need to toss somewhere that for whatever reason I do not want on my main OS/2 boot drive
3) all of HDD2 is basically a DATA_STORE, meaning things like ISO files, etc.
This is all running JFS, HPFS only exists on a 4G ramdrive (which is the temp space while OS/2 has booted and is running, fast).
If I had to do it all over again, here is what I would do:
1) size up the MAINT partition to give me a runable WPS environment
2) separate the OS partition as per the recommendations you covered
3) build a separate partition that's for programs
4) possibly build a separate partition that's for data
#3 & #4 could go on the same partition, it really depends on how much data movement we are talking about, size of datasets, etc., each configuration will be unqiue.
I use a nifty little utility to build the MAINT partition with, it's called BOOTOS2 and you can find it here =>
http://hobbes.nmsu.edu/h-viewer.php?dir=/pub/os2/util/system&file=bootos2.zip&backto=%2Fh-search.php%3Fkey%3Dbootos2%26pushbutton%3DSearch.
EDIT
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Oh...almost forgot, it totally makes sense these days to simply build yourself a bootable USB stick which basically becomes your MAINT partition. I haven't gotten around to doing just that, but that'll probably be my very next project...best to be ready in case the SDD or HDDx take a dump on ya!