PC Hardware in a Nutshell, 3rd Edition

Working with Obsolete Diskette Formats

If you’ve been computing for a long time, it’s sometimes necessary to read a diskette written in an obsolete format. You may also need to format and write a diskette in an obsolete format—e.g., to create a boot diskette for an older system whose hard drive will not boot but still contains valuable data. If you find yourself in such a position, keep the following issues in mind:

• A 3.5-inch 1.44 MB FDD can read, write, and format 720 KB (DD) and 1.44 MB (HD) diskettes. 3.5-inch 2.88 MB (ED) diskettes are readable only by an ED drive. These are difficult to find new, so your only option may be to locate someone with an ED drive who is willing to allow you to use it to transfer your data.

• A 5.25-inch 1.2 MB FDD can read any 5.25-inch diskette written with an IBM format in any 360 KB or 1.2 MB drive. A problem may arise when you exchange 360 KB diskettes between 360 KB and 1.2 MB drives. 360 KB drives write a wider track than 1.2 MB drives, which cannot completely erase or format data put down by 360 KB drives. If a 360 KB drive formats or writes to a 360 KB diskette, a 1.2 MB drive can subsequently read, write, or format that diskette, but once that diskette has been written or formatted in the 1.2 MB drive, it will no longer be reliably readable in a 360 KB drive. This problem does not arise if the 360 KB diskette has never been written to in a 360 KB drive. Accordingly, if you need to write data with a 1.2 MB drive that must subsequently be read ...