Twinstar UMB (TWINUMB) is a device driver that unlocks Upper Memory Blocks (UMBs) on PCs equipped with the UMC UM82C330 / UM82C336F chipset. This chipset, often referred to as "Twinstar", is found in certain 386SX systems manufactured around 1990-1991.
TWINUMB activates the shadow RAM feature managed by the chipset, repurposing it as usable UMB space that can then be enabled via tools like USE!UMBS.
This driver functions as an initializer, meaning it does not remain resident in memory. It is a device driver, hence you need to load it using a "DEVICE=" directive in your CONFIG.SYS file.
More information can be found in the program documentation.
Download:
TWINUMB 1.1
TWINUMB 1.0