The somewhat vague documentation that Commodore supplies with its products leaves the field wide open for independent authors. The disk drive manual is a prime example. So it's not surprising that enterprising authors should try to bridge this gap. A brief introduction is followed by a chapter on powering up, although it does not include multiple connection of disk drives and printers.

Chapter two describes the construction of a diskette with the aid of an exploded diagram, and offers good advice about their care and maintenance. Following that, the Basic disk commands LOAD, SAVE and VERIFY are explained in detail, together with pattern matching, and the wedges system supplied on the Demo disk.

All the disk maintenance commands are explained, but the examples tend to be no better than those in the original manual, and are so embedded in the general text that they are difficult to identify at a glance. The authors give a warning about using the SAVE and REPLACE option of the SAVE command. They claim that there is a bug which may corrupt the disk (perhaps Tommy could comment on this).

The next three chapters cover Sequential, Random Access and Relative file systems. Error checking and the use of the status variable are introduced with short program examples, as are reading and writing files. A very useful subroutine is given to change floating point numbers into strings to reduce their storage space on disk.

The chapter on Random Access files details the mechanics of reading and writing to specific areas on the disk, and mentions that a Sequential file is required to keep track of the records created. Unfortunately no detail is given on how to create and maintain such a file.

The remainder of the book contains useful tables of commands, and comprehensive explanations of each error message.

Four useful programs are included to display the contents of a Sequential file, unscratching a SCRATCHed file, software write protection of a disk and changing the name and ID of a disk without NEWing it.

The book claims to be a simple guide to using your disk drive. It is basically a replacement for the original manual, and goes no further than explaining the workings of the disk. It will not help beginners to design file handling programs. Ian Sinclair's book represents better value.