I see that Dave pointed you to the setup for the AOS RAMDISK. It is part of the new OS2LDR. RAMFS.IFS may be included in ArcaOS, but I recommend not using it.
1) ZIP processing - I use 'RPF Zip Control'
Ouch. That is an ancient program, that I quit using many years ago, simply because there are better ways to do zip/unzip. ARCHIVE Tool is one of them, and it is part of ArcaOS.
2) PMMail - just the standard attachments that you open up in the email, I see pmmail dumps them out into a file, so similar approach to #1 above, but because the filesizes are so much smaller it's barely perceptible
PMMail (3.x) has a setting to point to the drive, and directory, that you want to use for temporary files. Where it makes the biggest difference, is when you use the option to compress the message files, in a folder.
3) GCC - ahh, this is the biggest beneficiary actually...running any compile process (as I have it setup right now) causes the various object files to be created, I'm simply telling GCC to use the ramdisk instead of the disk, literally this almost gives a feel of an all in-memory process short of reading the sources and libraries
Okay. I thought that is probably what you meant, but what you said could confuse people.
I used ramfs for quite a while and it works well, the memory it allocates is swappable and doesn't affect things like shared memory. The problem is that it doesn't quite work right with symlinks for some reason.
Actually, there are a lot of things that don't work quite right, with RAMFS.IFS. I don't remember the details, but it wasn't possible to use it with some program that I was using when I found out about the limitations. The ArcaOS RAMDISK (which is the same as what QSINIT uses) is far better, and it can use the HPFS file system (it is one of the settings), which gives it the full capability of the HPFS file system. If you have enough memory, you can use more than one RAMDISK, with different file systems, but I can't think of any good reason to do that. The memory above 4 GB also has a method to use it as program storage (when not using it as a RAMDISK), but it needs an API to make that more useful. (look it up in the QSINIT documentation).
I didn't use ramdisk.ifs much because it used otherwise valuable memory. With the ramdisk in AOS, I have a 20MB ramdisk used from otherwise unused memory. I have my swappath set to it as well as temp and Mozilla temp space. My primary reason for using it for these is to limit writes to my SSD.
The AOS RAMDISK is most useful when you have more than 4 GB of memory. I have 8 GB of memory, and use a 4.5 GB RAMDISK, without taking more than a few bytes (for the driver), away from my main memory. When you have 4 GB of memory, for OS/2, you will never swap. I would suggest, that 20 MB is pretty small, for a swap disk. One of my systems is only 3 GB, and I allocate a 1 GB RAMDISK from it, but I don't use it for swapping, mostly because a 2 GB machine will rarely swap anyway, and if it does, 20 MB isn't going to help much.