First post, by Tiido
- Rank
- l33t
Here's a growing collection of UMB drivers I have been making. Each driver has its own little section and download links of driver and the documentation are in the end of each section.
Next in line are OPTi 82C895 chipset, SiS471 and SiS496. UMC chipsets would be good to do aswell and some 386 chipsets too that I have around here but documenation seems not to exist... It would be great to compile some sort of repository of datasheets and register references of all the chipsets out there.
All these drivers have zero conventional memory footprint and reside entirely in the UMB, and even there they only take less than 200 bytes of memory for themselves.
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UMBARIES.SYS - UMB driver for Intel 420EX (Aries) chipset
The past few days I worked on making my very own UMB driver, with intent of getting stuff going with some 486 chipsets without introducing EMM386 in the mix. First target is the Intel 420EX (Aries) chipset since there's nothing out there with support for it. After a bunch of hurdles I have something that appears to work (though there's one serious problem) :
i420EX lacks ISA DMA into UMBs, which has implications for floppy access. LOWDMA driver from UMBPCI can help here. Eventually I plan to add such functionality into UMBARIES itself since I'm sure I can use a bit less memory doing things that way.
I also plan to add few non UMB functions too, for example the BIOS on my machine disables IDE controller entirely when there's no HDD connected to it (I use a SATA RAID card to break the HDD limits, since XTIDE didn't work on this machine) and this prevents me from using CD-ROMs on the onboard IDE connector.
LOADHIGH / LH command fails in MS-DOS 7.x, things just freeze, unless you have the lastest BIOS 1.00.08.AY0. DOS 6.22 and FreeDOS work properly always. Link to Final BIOS
Intel 420EX Driver - Documentation
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UMBALI.SYS - UMB driver for ALi M1489 (FinALi 486) chipset
This driver was a continuation of the Aries driver, using same code but with chipset detection and config specific to the ALi chipset.
M1489 does support ISA DMA in UMB region and there's zero headaches around it unlike 420EX chipset, but due to chipset limitations the entire UMB area loses write protection, this means that bad software can overwrite something in BIOS area and cause a crash etc. and unfortunately the BIOSes on these boards are modern types with differing content in shadow and EPROM/Flash so you cannot just disable shadowing either as you could with Video BIOS. It is suggested you do disable video BIOS shadowing to prevent accidental erasure of its contents.
T-04YBSC, a new YMF71x based sound card & Official VOGONS thread about it
Newly made 4MB 60ns 30pin SIMMs ~
mida sa loed ? nagunii aru ei saa 😜