UHDD DOS Device Driver =========================================================== 1. Description ----------- UHDD is an improved disk-only caching driver. It works like UIDE and handles up to 10 BIOS disks of all sizes, including A: or B: diskettes, on up to four UltraDMA controllers. Because SATA controllers support two drives per controller, only the first 8 SATA sockets will be used by UHDD on a SATA-only PC. This limitation does not affect UDVD2. When loaded after UHDD, the UDVD2 driver (see Section 4) will call UHDD to cache CD/DVD data. With cachesof any size, UHDD uses Read-Ahead for its UltraDMA disks; and with an /O switch, disk UltraDMA and cache tasks will overlap. Using both gives UHDD up to 20% more caching speed than UIDE. UHDD's cache is in XMS memory and can hold up to 4 Gigabytes of data. Its /B switch also sets a basic UltraDMA disk driver (no cache) requiring 128K of XMS as a buffer for I-O not suited to UltraDMA. The basic UHDD is far smaller than UIDE's basic driver and can handle tests or other non-cached work. UIDE should ONLY be used by people who still do not have enough disk space for using UHDD and UDVD2 together on their boot disk (in spite of UHDD now being so small!) or if no XMS is available: UIDE has fewer features, but it can work without XMS without caching, with very limited performance (see /N3 option). The small CC.COM "Clear Cache" program can help verify files written by UIDE/UHDD. Entering CC at a command prompt makes the caching driver "flush" its cache. Disk data (NOT data still in cache!) can then be compared v.s. the original output. Note that some CompactFlash cards cause CC to execute very slowly. 2. NO Warranties ------------- UHDD is offered at no cost, "as is", "use at your own risk", and with NO warranties, not even an implied warranty of FITNESS for any particular purpose nor of MERCHANTABILITY! 3. Switch Options -------------- UHDD usually needs only a /H switch to load in the HMA, a /S switch to set a cache size, and a /O switch to enable DMA/Caching Overlap (best, for most systems!). A summary of all UHDD switches is as follows: /A Requests "alternate" addressing for "legacy" IDE controllers, 01E8h/0168h for the first one, 01F0h/0170h for the second. /A is rarely needed. Without /A, the first "legacy" controller will use 01F0h/0170h and a second uses 01E8h/0168h as is usual for PC mainboards. /B Requests a "basic" UltraDMA disk driver (no cache) requiring 128K of XMS as a buffer for I-O unsuited to UltraDMA. /E Makes the driver call the BIOS for any hard disk I-O request. /E avoids setup trouble on some DOS emulators (VirtualBox, etc.) that do not emulate all PC hardware logic! /E also allows using hard disks on 1994 or older PCs which have no UltraDMA or no PCI/EDD BIOS. If /B is given, /E is ignored. UHDD automatically uses the BIOS if no UDMA is available, so the /E option is only useful because it saves some RAM to keep the whole UDMA engine unloaded if you know beforehand that your system will not be able to use UDMA, but it is not necessary to use /E and lose a lot of speed just out of caution. ***** NOTE ***** Using /E on protected-mode systems (JEMM386 etc.) may LOSE much speed, as a newer BIOS may omit "Virtual DMA" support and force disks to run in PIO mode! If /E is required, a DOS system should run in real-mode (UMBPCI, etc.) whenever possible. /H Puts most of the driver in "free HMA" space. To use /H, the driver must load from FDAUTO.BAT (not FDCONFIG.SYS), since FreeDOS provides no "free HMA" until FDAUTO is run. /O Overlaps disk UltraDMA with caching tasks, for faster speed. Although preferred, /O may NOT work on old/odd/"cheap" PC mainboards unable to do UltraDMA and access XMS memory at the same time! Systems should be tested, using /O. If disk errors occur, but CD/DVD input via UDVD2 works fine, /O must NOT be used! /Q Awaits "data request" before starting UltraDMA I-O transfers. /Q is rarely needed, only for old systems where the driver loads O.K. but seems unable to transfer data. /Q is NOT for use with Sabrent or other SATA-to-IDE adapters that do not emulate "data request"! /R15 "Reserves" 15-MB or 63-MB of XMS, for old DOS "game" programs /R63 which require XMS memory below 16- or 64-MB. The drivers must be able to reserve this memory, reserve their own XMS memory beyond that, and then "free" the 15/63-MB XMS. If not, the drivers display "XMS init error" and abort! /R for UDVD2 is ignored if it loads after UHDD, as UDVD2 will then "share" UHDD's XMS memory. /Snn Specifies the desired cache size in megabytes of XMS memory. Values for /S may be any number from 5 through 4093 (four Gigabytes). If /S is omitted or invalid, a 20-MB cache is set. UHDD displays "XMS init error" and aborts, when not-enough XMS is free! If so, request a smaller cache. /Z Moves protected-mode XMS data in 8K blocks (not 64K) for 486+ CPUs and 4K blocks for slower 386 CPUs. With JEMM386, /Z is unneeded. When other EMM/VCPI/DPMI drivers are used, PCs must be tested to find if /Z is needed. BAD schemes, that allow not-enough interrupts during an XMS move, could still be in use! For all switches, a dash may replace the slash and lower case letters may be used if desired. 4. Example Configuration Files --------------------------- A) Small real-mode systems that need only XMS may use this FDCONFIG.SYS example file: .. .. DOS=HIGH DEVICE=C:\BIN\XMGR.SYS .. .. Etc. .. B) Real-mode systems with V3.70+ UMBPCI and XMGR do not need the LOWDMA driver, as XMGR sets an "I-O Catcher" for UMBPCI. This scheme uses NO low memory, if /W is given; XMGR and other drivers go directly to UMBPCI "Shadow RAM" upper memory! An example FDCONFIG.SYS file is: .. .. DOS=HIGH,UMB DOSDATA=UMB DEVICE=C:\BIN\UMBPCI.SYS DEVICE=C:\BIN\XMGR.SYS /W .. .. Etc. .. C) A protected-mode system with XMGR and JEMM386 can use XMGR's "boot", taking only 384 low memory bytes as its 32-entry "XMS Handles" table (used early by JEMM386). See Section 6 below for other notes about protected-mode! An example FDCONFIG.SYS file is: .. .. DOS=HIGH,UMB DOSDATA-UMB DEVICE=C:\BIN\XMGR.SYS /B /N32 ;32 Handle XMGR "boot" DEVICE=C:\BIN\JEMM386.EXE I=B000-B7FF ... DEVICEHIGH=C:\BIN\XMGR.SYS ;Loads the runtime XMGR .. .. Etc. .. When all above drivers are loaded, other needed FDCONFIG.SYS files such as SETVER, ANSI.SYS, etc. can then load in any desired order. For each of the above examples, FDAUTO.BAT can then load UHDD and UDVD2 (or just UIDE) using the DEVLOAD program. This permits the drivers to use "free HMA" and save low memory. UDVD2 must load after UHDD, so it will find UHDD in memory and "link" to it for CD/DVD data file caching. The /O switch can also be used if desired; see Section 3 above for more details on why you may want to do this. Example FDAUTO command lines are: .. .. Int 13h drivers cached thru UHDD/UIDE .. load now and can load in upper memory. .. DEVlOAD /H C:\BIN\UHDD.SYS /S500 /H /O ;Or UIDE alone DEVLOAD /H C:\BIN\UDVD2.SYS /D:BLURAY1 /H LH C:\BIN\RDISK.COM /S250 ;Optional .. .. Etc. .. 5. Revision History ------------------------ 8-Jun-2021 UHDD.SYS is now 5601 bytes, down 140 bytes and taking only 11 sectors (not 12) for "boot" disks or other small systems. UHDD runs up to 10 BIOS fixed disks using up to 4 UltraDMA controllers. This saves 96 bytes of "free HMA" and may help with really "loaded" PCs. UHDD now permits ALL cache sizes, from 5 MB to 4093 MB (4 Gigabytes), so old PCs with <= 16-MB can set 5/6/7/8/9-MB caches as needed. All cache sizes now do Read-Ahead and can do DMA/Caching Overlap (with /O) giving improved "full speed" for the small caches below 10-MB. If FreeDOS users want only a 5-MB cache, it is now ~ 6% faster in protected mode. Those using 8- or 9-MB caches gain even MORE speed! "VDS" calls (for protected-mode JEMM386/etc. moves) now test the BIOS "VDS" flag at 40:7B before issuing such calls. No help for protected-mode, but it totally AVOIDS the calls in real-mode, for faster speed. 14-Jul-2020 UHDD's /O switch now enables DMA/Caching Overlap! That and Read-Ahead allow UHDD up to 20% faster caching speed than UIDE on V6.22 MS-DOS and similar speed gains for FreeDOS. See the comments about UHDD /O in Section 3, above. Due to Overlap, UHDD now runs up to 20 BIOS disks (was 22). 7-Jul-2020 All 10-MB+ caches are added to help old small-memory PCs. For 10-MB+ caches, Read-Ahead is used for UltraDMA disks. Default cache size is 20-MB, if /S is omitted or invalid. BUG fix: Controller-number masks are now 03Ch (not 01Ch), to handle 9 controllers properly. BUG fix: Init logic does not clobber disk "LBA48" flags. 31-Mar-2019 UHDD now uses Read-Ahead for its UltraDMA disks with 20-MB+ caches (10% more speed than UIDE). The caching UHDD now uses 2752 bytes (720 upper/DOS memory + 2032 HMA); the /B non-cached UHDD is unchanged. README file updated. 16-Mar-2019 README file updated. UHDD.ASM changed to note UDVD2 must load AFTER the UHDD driver (not before!) to cache CD/DVD data. No code changes, UHDD still dated 15-Feb-2019. 15-Feb-2019 2576 bytes (720 upper/DOS memory, 1856 HMA) for the caching driver and still 1328 bytes (576 + 752) for the /B non-cached driver. 10-MB and all 20-MB+ cache sizes added, for old systems with small memory. Default is still 80-MB if UHDD's /S switch is omitted or invalid. The 5-MB cache has 16K cache blocks, the 10- and 15-MB caches have 32K blocks, and the 20-MB+ caches use 64K blocks for faster speed. Maximum cache size is still 4 Gigabytes (really 4093-MB; 3-MB held for UHDD's cache tables [max. 1-MB] and mainboard control regs.). The 5-Mar-2015 UDVD2 can still call this UHDD to cache CD/DVD data files; no UDVD2 changes needed. If LBACache is wanted, the non-cached UHDD /B can still load first to provide disk UltraDMA. The "80386 errata" commands used by Ninho on his 386/SX are added. SSDs and CompactFlash cards with an ATAPI flag are run as UltraDMA disks, not as slower "Call the BIOS" drives like in UIDE. Disks over 128-GB now use only LBA48 commands, to stop disk ERRORS at exactly 128-GB when an LBA28 command "crosses OVER" that limit. All disks less than 128-GB still use LBA28 commands. NOTE: UIDE has not been so updated but can still be used on older systems. For newer systems, UHDD + UDVD2 are preferred. 5-Mar-2015 UHDD now handles 9 controllers, 22 BIOS disks or diskettes, 4 CD/DVD drives. UHDD binary-search buffer is again 512 bytes. UHDD "CD/DVD" cache deleted. Other drivers unchanged (re-dated only). 24-Nov-2014 UHDD "User" caches deleted, due to non-use. 14-Nov-2014 UHDD now "overlaps" UltraDMA disk input AND output with as many caching tasks as possible, for much improved speed! 19-Oct-2014 UHDD "overlaps" cache work during UltraDMA disk output and disk sector "gaps" at I-O end, for more speed! UHDD /M switch deleted, 256-byte search buffer is now permanent. 27-Sep-2014 New UHDD /M switch sets a 512-byte binary search buffer. 26-Jan-2014 UHDD offers "Common" & "CD/DVD" caches. 12-Jan-2014 "Stand alone" UHDD re-added, for use as needed. 12-Dec-2013 UHDD deleted (low use). 21-Nov-2013 UHDD old style "stand alone" driver re-added. 9-Sep-2013 Possible but unlikely UHDD exit errors corrected. 2-Sep-2013 UHDD /N1 size reduced. 30-Apr-2013 UHDD can now run without XMS (lower speed) for tests and FreeDOS "scripts". 15-Oct-2012 UHDD again detects A: and B: diskettes from BIOS data, NOT from "Int 13h" calls that FAIL with an LS-120 drive! 2-Aug-2012 UHDD "disk only" caching driver added. 6. Error Reporting --------------- UHDD works as a "BIOS driver" and returns whichever codes are set for diskettes and hard-disks handled by the BIOS. For SATA and IDE hard-disks, UHDD can post the following error codes: Code 0Fh - DMA error. CCh - Disk is FAULTED. 20h - Controller busy. E0h - Hard I-O error. AAh - Disk not ready. FFh - XMS memory error. Many DOS programs display only "Disk Error" messages with NO code, thus disk errors may require running a diagnostic to get better information! 7. Technical Notes --------------- Protected-mode users must pretest "I=nnnn-nnnn" or "X=nnnn-nnnn" values for JEMM386, as its "I=TEST" or "X=TEST" options may fail on newer PCs. Protected-mode is unrecommended with old DOS games needing reserved XMS as JEMM386 takes some XMS memory first. Newer "cheap BIOS" mainboards now OMIT logic used only by DOS and need an UltraDMA disk driver loaded before JEMM386 sets V86 protected-mode! For such boards, FDCONFIG.SYS example C above requires drivers cached thru UHDD, then UHDD itself, to load only in LOW memory directly after XMGR sets up XMS for the system. UIDE is unrecommended in this case as it will take FAR more low memory! JEMM386 can then load and set V86 protected-mode, and UDVD2 (if wanted) can be loaded later from FDAUTO. 2015 or older PCs with a normal BIOS usually do not need this and can use example C as shown above. Use of JEMMEX or other "EMM" drivers but JEMM386 must now be avoided. Other "EMM" drivers got dropped long ago, some with leftover ERRORS! JEMMEX has caused crashes on newer PCs due to OBSOLETE XMS detection code, and it cannot work with UIDE/UHDD on a "cheap BIOS" board as neither driver can load O.K. if the other is absent! To run protected-mode on "cheap BIOS" boards, use FDCONFIG.SYS example C with UHDD/UDVD2 (not UIDE) and the changes noted herein, and be aware that JEMM386 will be REQUIRED! XMGR and UIDE/UHDD/UDVD2 will return normal XMS and CD/DVD error codes, as needed. They are listed in the "V3.0 XMS Specification" and in the Microsoft "MS-DOS CD-ROM Extensions 2.1" document. Both are available from Microsoft or from other Internet sources. UIDE and UHDD work as "BIOS drivers" and return whichever codes are set for diskettes and hard-disks handled by the BIOS. For their SATA and IDE hard-disks, UIDE/UHDD can post the following error codes: Code 0Fh - DMA error. CCh - Disk is FAULTED. 20h - Controller busy. E0h - Hard I-O error. AAh - Disk not ready. FFh - XMS memory error. Many DOS programs display only "Disk Error" messages with NO code, thus disk errors may require running a diagnostic to get better information! UIDE/UHDD handle only "Legacy" or "Native PCI" IDE controllers. RAID- only chipsets, port multiplier chips, or ADMA chipsets are unsupported. UIDE/UHDD must use "Legacy", "Compatibility", or "Native IDE" mode with AHCI controllers. For mainboards with no such controller settings, a Sabrent or similar SATA-to-IDE card can let UIDE/UHDD/UDVD2 handle SATA disks/CDs/DVDs from parallel-port IDE controllers (80-pin cable) at DMA speeds. "Add on" PCI-bus adapter cards that can be detected by normal PCI-bus routines may also be used for disks/CDs/DVDs. XMGR loads in UMBPCI upper memory that is not "provided" to the system. With UMBPCI, a "MEM" list may begin with a block having a 00A5h offset, or greater with 80 or 128 XMS "Handles". The upper memory skipped by this offset contains XMGR. The UMBPCI upper memory manager uses system "Shadow RAM" that cannot do DMA. A newer BIOS may use UltraDMA to load programs in upper memory. If this is "Shadow RAM", a HANG can occur! These two rules apply, if using UMBPCI with XMGR and UIDE/UHDD: A) V3.70+ UMBPCI must load before XMGR, so XMGR finds UMBPCI and sets its "I-O Catcher", to handle diskette "Shadow RAM" DMA forever and to do disk "Shadow RAM" UltraDMA until UIDE/UHDD can load. Older UMBPCI drivers, or other UMBPCI load schemes, are not recommended! B) When CHS I-O is done, each disk must have valid CHS parameters set in the BIOS. If not, the "I-O Catcher" or UIDE/UHDD let the BIOS handle CHS I-O. If BIOS UltraDMA is left enabled, a "Shadow RAM" HANG can occur! Old BIOS programs may not configure a mainboard controller when no user drives are on it! The drivers then display "BAD controller" and go on looking for others to use. If this message is given, users must check that all SATA/IDE drives are set "active" with the BIOS setup routines. If so, "BAD controller" means a chip is not using "Bus Master" and "I-O Space" modes, and a BIOS update is needed!