Polyzap. This is the disk based assembler provided with the Polydos package. It has all the usual assembler features such as pseudo operations which allow conditional assembly, object file definition and the ability to reference previously created symbol files. The ability to use previous symbol files is very powerful and is illustrated by the fact that a file called “SYSEQU.SY” is provided on the master disk which holds all the equated values relating to Polydos workspace, NAS-SYS workspace, subroutine numbers and ASCII character codes. Instead of typing a list of equates in at the start of each program, a statement referencing the file can be used and then a line such as:

DEMO    SCAL ZB2HEX ;this routine converts binary to hex

may be used which saves lots of tedious typing. There are several other features which are available at assembly time such as force second pass, create symbol file, list symbol table, assembly listing to printer with heading plus a few others.

Summary. The package is well presented and very well documented although there are various spelling mistakes in the manual which one does not expect when so much trouble has gone into the rest of the system. The availability of a decent Nascom oriented disk operating system is a relief since the only other real option is CP/M – a silly choice as you have to throw away your existing software, get 64k of RAM and a Gemini 80x25 IVC card to get the best from it and after that you do not have a Nascom anymore, just another machine which runs CP/M! (Note also that CP/M does not include any form of BASIC or even a Z80 assembler which would together cost in the region of 200.00!). Polydos was purchased from EV Computing in Manchester but is available from your friendly local Microvalue dealer for a fee of 90.00 plus Maggie’s bit, which considering the cost of ZEAP, Programmer’s aid and Naspen (which are not required) is excellent value for money.