resort, one could try to find someone with MAC.COM and request him to assemble
the files for you.
This is the main problem facing the installer. If M80 and L80 are not
available, it means that the utilities cannot be modified to any extent, but
this is no real problem since the normal performance is quite acceptable.
For the rest of the installation, everyone will have DDT.COM, which will be
sufficient. Since there are several ways of tackling the various problems,
however, it is useful to review the alternative ‘tools’.
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Editors. It is necessary to carry out editing of the various .LIB files
associated with Z3 and the segments, and the BIOS source code as well if
available. Since most people will have their favourite editor, there is
not much to say here. It should be borne in mind though, that some source
files are too long to fit into RAM, so that editors like ED or WordStar
might be needed. (Minor changes can be made with a disk editor like
SPZ.COM, which can be quicker and easier then using an editor.)
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Assemblers. If MAC.COM is available, then the problems referred to above
will not appear. The availability of M80 and L80 will permit the utilities
to be freely altered.
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Debug Utilities. DDT.COM, ZSID.COM, 28E.COM (PD), GEMDEBUG.COM. The main
advantage of DDT and ZSID is that they can ‘LOAD’ HEX files. Loading .HEX
files under DDT or ZS1D is not difficult, but error prone due to the need
to use variable offsets. I much prefer to overlay using GEMDEBUG. The
latter is not so sophisticated as DDT or ZSID, but has a much better screen
display, command structure and several other useful features.
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Loading Utilities. If LOAD.COM is used to load .HEX files, the results are
not exactly useful, when the target address is in high RAMI!!. If
MLOAD23.COM (PD) is available, then it is easier to MLOAD the .HEX file,
and to use the result as an overlay or Z3 segment. For example, assume
that the 2k Byte Z3 CCP is to reside at C800H, as in my current system.
After assembly of ZCPR3.ASM, if MLOAD is applied to ZCPR3.HEX, I am left
with a disk file 2K long, with addresses loaded for C800H, that can then
easily be used as an overlay.
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Disk Editors. Where a number of bytes might need to be changed, as for
example to alter names in a named directory segment, to alter the default
path on the system track of the disk, to change the assembly address of
BDOSZ (56k long), to patch the startup command in the system image cold
boot routines, then I increasingly use a disk editor. My favourite is
SPZ.COM (PD). It has a very friendly user interface, and can cursor edit
both ASCII and HEX bytes of a file or disk sector, which may be the system
tracks, or directory data. DU.COM (PD) in one of its many versions is also
very versatile, but I find SPZ so much pleasanter to use. (A version of DU
accompanies Z3, end it is more interactive than earlier versions.)
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Other Utilities. One of the several PD utilities such as BDOSLOC, FINDCCP,
LOCATE, Z3LOC to discover the operating CP/M system addresses makes it much
easier to find out about system addresses, especially if the installer is
not used to system work.
ZCPRS Installation – Some Suggested Methods
Once it has been decided which Z3 segments and buffers will be implemented, a
memory map should be drawn up. In the installation information supplied with
Z3, it is suggested that certain areas are preset to all 00’s. The main reason
for this is to avoid system problems that could occur after the system is
booted, if spurious data is left in any of the system buffers, and these are
accessed before segments are loaded (which is by no means impossible).