This is 4x4MB RAM, huge comparing to other models of the time.
Floppy Disk Drive
Hard Disk Drive
This is not the original drive for Macintosh IIsi, the original drives were 40, 80 or 160MB large. This is also not an Apple branded drive and needs to be initialised using a patched version of the disk tool.
1080MB, IBM DPES-31080