X-Listprocessor-Version: 8.1 beta -- ListProcessor(tm) by CREN It is not a BIOS trick. The extra 128K appears in the upper memory area, from D000 to EFFF. There was a special device driver available, USE!UMBS.SYS, that turned this memory into UMB's if you were running DOS 5. Great for parking mouse and network drivers in. The driver was written by a hobbyist as a memory study project, it was available with the machine code source so you could modify it for other computers. IIRC it should be on Simtel. I also have a copy around here somewhere. I used to admin a network that had lots of Philips XTs, NMS9100 and P3105 were the ones that had this extra memory. Kees --