A fully detailed analysis of the operating system would be very lang and tedious, and might still fail to provide answers to all the questions that are likely to arise. What is attempted is an analysis of the more important functions, the rest being covered by shorter descriptions.
It is assumed that the reader has some knowledge af machine code. The inclusion of a complete tutorial on Z80 programming would leave little or no room for anything else. For those who need such help, the well—known book [[Programming the Z80]], by [[Rodnay Zaks]], is recommended. However, a study of the various operating system routines in relation to the descriptions given hereafter may prove enlightening, even to the merest tyro.
A key difficulty in this connection is that some disassemblers will only access code in ROM. A program given in the Appendix provides a solution, since lt will work fron ROM—borne code, while another program in the Appendix provides convenient means for calling the various functional routines and checking their action.
The book is based an version l.Ø of the ROMs, but the comments can largely be applied to other versions by working from the jumpblock entry points, which should remain at the addresses given, even though they access different entry points in the ROM code.
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