Are you sure your system memory is working okay? I remember I got mysterious compression errors too, and could lay the blame at a faulty SIMM. Replace the memory and see what happens.
As to your question about the mountlist: it contains information about the type of thing you want to mount, but which the device is unable to supply for itself. Floppy drives come to mind. In many cases, you don't need all the things listed in the mountlist you posted. However, you can achieve very funny effects with them. For example, you can make a copy of this mountlist, then change both so that their LowCyl/HighCyl entries read
LowCyl = 0
HighCyl = 1444
and
LowCyl = 1445
HighCyl = 2890
If you save both under a different name (say ZIP0 and ZIP1), you can mount them both, using the same ZIP-disk. In other words, you now have two file systems on a single physical disk. You can format them, copy files between them, and so on... Quite funny to try that. Make sure you use an old ZIP-disk for this experiment, and issue a 'format ZIP0:' and 'format ZIP1:' before use. You can assign a different filing system to ZIP1 too if you like.
