The 128KiB of RAM was painfully insufficient even with so much shifted to ROM: text files couldn't be more than a few pages in length. And there was no backing

The 128KiB of RAM was painfully insufficient even with so much shifted to ROM: text files couldn't be more than a few pages in length. And there was no backing store you could reliably swap OS components into either, because the machine had a single floppy drive and no hard disk, and the floppy disk had to come out to allow disk copying.