I am now using your updated version with an IBM PC 5150 which has two original IBM 64/256KB Memory Expansion Option cards in it. These cards actually allow putting RAM into the A000-AFFF segment (typically used by EGA and VGA graphics cards). That configuration can be used if one has a CGA, Hercules or MDA display adapter.
Maybe you could implement the functionality of CLEARMEM.SYS into USE!UMBS.SYS with a parameter like /ZEROFILL which would write zeroes into the configured upper memory blocks.
Thanks for the feedback and apologies for not responding sooner! Back when I did this I had apparently missed the discussion regarding parity errors and the need for something like Chuck's CLEARMEM.SYS, not to mention the fact that other people had already added command line parameter support.
Also;
I don't know what I had been smoking that day because this command line will leave the last paragraph (16 bytes) unused. The correct line should look like this;Example CONFIG.SYS command line for a single 128 KB UMB starting at segment D000h:
Code:DEVICE=USE!UMBS.SYS D000-EFFF
Code:
DEVICE=USE!UMBS.SYS D000-F000
View attachment USE!UMBS.ZIP