In what looks like another lifeline for MS-DOS and another blow to OS/2, a very low-cost solution to the problem of expanding memory beyond the 640Kb limit of MS-DOS is now available. Designers wanting to implement the Lotus-Intel-Microsoft Expanded Memory Specification 4.0 in their AT-alikes can now do so with a single chip rather than taking up one of the expansion slots and using add-in boards, courtesy of the folks at Chips & Technologies Inc, San Jose. The company offers the EMS Mapper chip – that name ain’t going to go too down well with Unisys Corp – at a mere $12.50 in OEM volumes – which translates to an end user price of about $40 against hundreds of dollars for the present solution, according to Microbytes. Called the 82C631, the chip has two banks of 64 registers that access the expanded memory and can switch from one bank to another with one input output instruction and requires no wait states when used with CPU clock speeds of up to 16MHz. The chip also contains a software controllable enable-disable feature, so that memory above 640Kb can be used either as expanded or extended memory. Four of the chips can be stacked together for a maximum of eight register banks, to support a maximum of eight tasks. Volume is promised for the second quarter, and the company says that at least two of its major OEM customers have already gone for the chip – it won’t say which, but Apricot Computers Plc, Zenith Data, Dell Computer and Tandy Corp are big Chips & Technologies customers.
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