Back in January 88, UPDATE began a series about EXTRA MEMORY. The first objective was to explore the ways and means of using EXISTING Extra Memory Hardware. Briefly these hardware devices are: The Oliger EPROM cartridges for Dock Bank use: The 32K non volatile memory cartridge for use in the Dock and XROM banks: The Aerco FD-68 Disk Controller which contains un-assigned extra Ram 64K blocks. Recently one more addition is the LARKEN Ram Disk cartridge.
The existing TS-2068 allows us to use programming to enable the Dock and XROM banks of memory when RAM or EPROM is installed in these two banks. There is no automatic way of using extra memory in the TS-2068, unless such auto usage is provided for by PROGRAMMING. So, the January UPDATE delved into the programming needed to use these existing devices, which generally had not been covered in sufficient detail for the devices to be widely accepted and used. This involved “collecting” pieces of data about programming from several sources and putting together a group of utilities to allow the user to move BASIC programs or utilities into the Dock or XROM banks and operate the programs. The UPDATE series on EXTRA Memory continued in tutorial form to include Operating programs in both HOME and DOCK banks and switching from one to the other at will. Then the Disk Drive was brought into the picture and utilities developed for Auto Booting programs into Home RAM, followed by AUTO MOVING the program into Dock bank, and then Auto Booting another basic program into Home Bank– to operate two programs at will. This effectively magnifies the SIZE of programs that the TS-2068 is capable of handling and frees up the FREE MEMORY (ram) for an extraordinary increase in DATA handling capability (within RAM).
The above represents the TOTAL capability of the TS-2068, as it was manufactured, to utilize MEMORY. We cannot go beyond using the Dock and XROM banks without re-designing the TIMEX ROM. AND, it isn’t easy for a user to get that far, because the user must learn programming to do it himself. The tutorials and utilities given in UPDATE were designed to allow a person who is interested in programming to learn how to do it, and for programmers to use to develop software to operate from Extra Memory.
UPDATE realizes that many users wont delve into the detailed study needed to become profficient in using Extra Memory, and that this series is of little interest to them. But there are some who are eager to extend their programming abilities. Then there is a small group of real hackers who want to go the limit and build onto the TS-2068. So, just as UPDATE plays to the novice programmers and to those who are interested in only using software, not constructing it, we also want to fill the needs of the intrepreneur and the expert.
ENTER CHARLES BOTHNER, to extend the series on Extra Memory “to the limit”. This issue brings another detailed article by Charles. In addition to his extensive project to extend Memory Addressing, Charles has given other building schematics. One is a Auxillary Power Supply to power external add on devices, which most of us need to prevent TS-2068 overload. I have already burned out one TS-2068 due to overloaded it with add ons. Hopefully one of our hardware builders will pick up on this need and offer a power supply that plugs on to the external Buss of the 68 and power everything else that is tagged on. WE NEED THAT!
In this issue, Charles casually verifies the previous UPDATE information about Dock and XROM bank transfers, and with a snort of impatience, he proceeds to the sublime, leaving most of us in a fog of miscomprehension. But not really. If you really dig in and cross reference the Timex Tech manual, things come into focus. A good many are digging this and are asking for more. We have some real technocrats using the TS-2068!
Actually, if you will notice, Charles does not apply TITLES to his works, just branch headers. If I had to coin a title, I would use: “ENGINEERING A Z80 BASED COMPUTER”. Then I might add: (“Using the TS-2068 as a Starter”). His works go beyond the UPDATE series title of Extra Memory while he stretches the Z-80 CPU to it’s limit. There’s a guy in England who did something similiar, and his product is called “The Sinclair Z88”. I don’t know where Charles Bothner is taking us, but UPDATE will continue with his works until the end. If someone really wants to learn the practical aspects of computer engineering, address coding, assembly language, and the Z-80 CPU, this is a GREAT tutorial on all of that.