osRe Posted August 30, 2012 Share Posted August 30, 2012 Am I correct in assuming I can run a 160GB HDD with Win98 and no BIOS support (which detects it as 8GB) as long as just don't use areas >137GB? It's the BIOS part I'm not sure about. Does it matter for anything other than DOS? Is booting affected? The boot partition is 2GB, so it falls within the 8GB detected by the BIOS. Link to comment Share on other sites More sharing options...
submix8c Posted August 30, 2012 Share Posted August 30, 2012 (edited) What's the MoBo Make/Model (you didn't say)? There are "patched" BIOS for some older ones (not TOO old).You could use a HDD DDO (Dynamic Disk Overlay) from the Manufacturer (you didn't say what Make/Model of it either). Edited August 30, 2012 by submix8c Link to comment Share on other sites More sharing options...
osRe Posted August 30, 2012 Author Share Posted August 30, 2012 The mobo is ASUS P2B, the HDD is a WD AAJB. But I don't want custom BIOSes or anything exotic, and I don't care about DOS as long as Win98 can boot the drive correctly.Beyond booting I'm already using something similar: a 500GB external drive with the initial ~128GB as FAT and the rest NTFS. I just don't know if booting might be affected by the BIOS misidentification. Link to comment Share on other sites More sharing options...
submix8c Posted August 30, 2012 Share Posted August 30, 2012 Highest BIOS (haven't tried the links):http://www.wimsbios.com/forum/topic10054.htmlAppears that a 32/64GB limit exists (maybe 120gb)?No "custom" BIOS for it.Do you understand DDO? Vendors of Hard Disks supply a SOFTWARE work-around for use on boards that don't support it. These do the job JUST FINE!There are various versions of the ASUS P2B - which ONE?What SPECIFICALLY is the HDD.You're answers are NOT specific.Have you actually used the External HDD on it? IOW, does it HAVE a "controller" in the enclosure (which BYPASSES the BIOS)?THEORETICALLY, as long as you have that "latest BIOS" it may misrepresent the actual size (being limited) but still be functional, although maybe not with DOS/Win9x, e.g. with WinXP after Boot to a within-range partition, will continue to function, ignoring the BIOS (AFAICR). Link to comment Share on other sites More sharing options...
rloew Posted August 30, 2012 Share Posted August 30, 2012 Am I correct in assuming I can run a 160GB HDD with Win98 and no BIOS support (which detects it as 8GB) as long as just don't use areas >137GB? It's the BIOS part I'm not sure about. Does it matter for anything other than DOS? Is booting affected? The boot partition is 2GB, so it falls within the 8GB detected by the BIOS.A DDO is not an option with Windows 9x. It is a necessity.Any operations by DOS or Windows, before the Driver is loaded, to Drives other than C: can fail. In particular if you do any installations to other Drives that need to be updated on the next boot, they are likely to be done by WININIT in DOS mode.I have DDOs (BOOTMAN) that can provide the necessary support as well as letting you use the full 160GB. Link to comment Share on other sites More sharing options...
Comos Posted August 30, 2012 Share Posted August 30, 2012 In the past when I was running Siemens-Nixdorf i486/100 & Win95OSR2 I had similar issue with the BIOS HDD size limitation.Then I disabled the detection on that IDE channel completely and windows during bootup detect the drive (<137GB) and I was able to use it. Link to comment Share on other sites More sharing options...
submix8c Posted August 30, 2012 Share Posted August 30, 2012 (edited) http://dmp.free.fr/telecharg/flopimage/Look for DLGMAKER.EXE - When run, it will create a WD DLG Diagnostics Disk (Version 2.8). This is the last known WD tool that makes a usable Overlay. I do NOT know if it will work with a HDD that size.Please note that DDO's are put in the Master Boot Record (1st sector and maybe 2nd, etc?)and you DARE not use "FDISK /MBR" or ANY other utility that writes to the MBR or the OS will no longer boot.The DDO can be "uninstalled" with the Floppy as well.Info/Warning and links from Microsoft (some links inside are no good). More info/a linkHTH and good luck! Edited August 30, 2012 by submix8c Link to comment Share on other sites More sharing options...
osRe Posted August 30, 2012 Author Share Posted August 30, 2012 (edited) submix8c, thanks for DDO link. I'm not comfortable with the idea of DDOs. Maybe if there were a generic one that could be loaded from AUTOEXEC.BAT or CONFIG.SYS, rather than MBR. But even then it's somewhat worrying.More specifics on the mobo and HDD: mobo rev 1.10. But the differences are likely in things CPU voltage support, etc., rather than anything pertinent here. HDD-wise, the only extra info there is is the non-documented suffix of the model (stuff like -00JJD0), which I could check if you're interested.Appears that a 32/64GB limit exists (maybe 120gb)?128GB/137GB is the BIOS limit.Have you actually used the External HDD on it? IOW, does it HAVE a "controller" in the enclosure (which BYPASSES the BIOS)?I used the external HDD. It's not used for booting, and it's on a controller card.But rloew brought up a good point. Some write actions can be done before Windows booting completes, and those might use BIOS functions. Even if the OS partition fits within the BIOS detected size, I actually do have an additional software partition that doesn't. If only the BIOS treated the HDD as 128GB, or even 10-20GB, that'd be enough, but 8GB is very borderline.Too bad there's no 128GB clamp jumper on the drive. I might solve the problem by doing more HDD rotations than I anticipated. :-/Then I disabled the detection on that IDE channel completely and windows during bootup detect the drive (<137GB) and I was able to use it.For a boot drive?! Edited August 30, 2012 by shae Link to comment Share on other sites More sharing options...
dencorso Posted August 30, 2012 Share Posted August 30, 2012 You want a safe, reliable, generic DDO, RLoew's is the best. It's not free, but it's worth the cost. All "partitioning schemes" used for HDDs beyond the BIOS detection are highly unsafe. These are my 2¢, of course. Link to comment Share on other sites More sharing options...
osRe Posted August 31, 2012 Author Share Posted August 31, 2012 Too bad there's no 128GB clamp jumper on the drive.Maybe setting the HPA or DCO max address will be just as good? Link to comment Share on other sites More sharing options...
dencorso Posted August 31, 2012 Share Posted August 31, 2012 The BIOS IDE HDD Limitations. To follow some of the links therein, you may have to use the Internet Archive's Wayback Machine, due to sites having disappeared into the ether... Link to comment Share on other sites More sharing options...
jds Posted August 31, 2012 Share Posted August 31, 2012 Too bad there's no 128GB clamp jumper on the drive. I might solve the problem by doing more HDD rotations than I anticipated. :-/Well, there is a virtual clamp jumper available. Seagate Tools for DOS gives you the ability to set any clamp size you wish. Just temporarily put the drive in a machine that can handle the current/native size, and run the tools from there. Note, this feature is not available in the MS Windows version of the tools.Joe. Link to comment Share on other sites More sharing options...
Foxbat Posted August 31, 2012 Share Posted August 31, 2012 The mobo is ASUS P2B, the HDD is a WD AAJB.What SPECIFICALLY is the HDD.AAJB is Western Digital's current line of Caviar Blue IDE hard drives. Link to comment Share on other sites More sharing options...
jaclaz Posted August 31, 2012 Share Posted August 31, 2012 Well, there is a virtual clamp jumper available. Seagate Tools for DOS gives you the ability to set any clamp size you wish. Just temporarily put the drive in a machine that can handle the current/native size, and run the tools from there. Note, this feature is not available in the MS Windows version of the tools.There is a similar thingy for WD drives:http://wdc.custhelp.com/app/answers/detail/a_id/936/~/operating-system-and-bios-limitations---137-gb,-32-gb,-8.4-gbjaclaz Link to comment Share on other sites More sharing options...
osRe Posted August 31, 2012 Author Share Posted August 31, 2012 (edited) The BIOS IDE HDD Limitations.Thanks. I'm generally aware of the cause for various limits. But this page is old, so no mention of 137GB. What I do wonder about is whether the 137GB limit is 65536 x 16 x 255 or 65536 x 16 x 256?AAJB is Western Digital's current line of Caviar Blue IDE hard drives.The current day AAJBs are probably different than a few years ago (the one I have is from 2006-7), but their "public" model number if the same. The exact details are probably indicated by the suffix (a few letters and numbers, I think 5 of them, e.g.: (WD1600AAJB-?????), but that isn't documented as far as I know.There is a similar thingy for WD drives:They just mention various limitations, but I don't think there's a WD tool to set it, but...Well, there is a virtual clamp jumper available. Seagate Tools for DOS gives you the ability...That's what I thought about. I don't know if Seagate Tools will work for a WD, but HDAT2 should. I'll try it in a while. Any idea if it's better to limit through setting the HPA or DCO (assuming both will affect BIOS detection)?EDIT: Well, it seems to work so far, using HPA.The limit seems not to be 2^28, but 65536 * 16 * 255 (267,386,880 sectors). Anything above, and it's detected as 8GB again (I suppose using CHS instead of LBA?), and strangely also on a 48-bit capable BIOS. Another thing, I used the 28-bit version of SET MAX. The 48-bit seemed not to be detected correctly, but I didn't pay enough attention so it could just be that I set it to more than the 267M limit.I guess I'll use a slightly smaller number to be on the safe side for 1-off errors (then again, if a 1-off is multiplied... maybe safest would be to set to something common, like the equivalent of 120GB HDDs). Edited August 31, 2012 by shae Link to comment Share on other sites More sharing options...
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