Adding On To Gladstone

Many memory expansion boards have been offered for ZX81’s and TS1000s. One of the first to break down through the $100 price barrier was the Gladstone 64K RAM pack. It gave you use of RAM memory from locations 8K through 64K. Its only short coming was that you had to ALWAYS use all of the 8K to 64K region. Many printer interfaces, peripherals, etc., are memory mapped to operate in the 8K to 16K region of memory. The circuit used by Gladstone and several other manufacturers, has no provision to disable the RAM pack’s control of this region of memory.