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Maxblast EZ-BIOS Question

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Grandcheapskate

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I have a DOS machine with a single 8.x gig hard drive using EZ-BIOS. I was thinking of putting a 540 meg hard drive in as the primary and moving the 8.x gig to the slave position. I started re-reading the Maxblast EZ-BIOS instructions and got a little confused. Maybe you can help.

The instructions state DOS cannot access a drive larger than 8.4 gig, with partition sizes limited to 2.1 gig. Does the 8.4 gig limit also apply when using EZ-BIOS or does EZ-BIOS allow you to break through that limit? I believe I used to think that EZ-BIOS allowed me to use drives larger than 8.4 gig but after rereading the instructions, I don't think it does. I believe EZ-BIOS is only needed when your motherboard BIOS is incapable of using LBA mode.

Am I right?

Thanks...Joe
 
Yes, it allows the use of larger drives when the BIOS is incapable on its own. In effect, it breaks the limit the BIOS imposes.

Don't forget, you can always boot from an EZ-BIOS enabled floppy to get to a drive with a DDO on it. Or, you can probably install EZ-BIOS on the primary HD to access the slave drive.
 
It's DOS itself that has the 8.4G limit. EZBIOS is only helping DOS interface to the drive to get you up to that limit. EZBIOS can only fix the primitives where DOS is interfacing to the drive- it cannot patch DOS to bypass the much larger problem of going above 8.4G

For the record, you'll likely have a hard time finding enough software for DOS to fill 8.4G of space. That's a nice problem to have. :)

huh. stone beat me to the posting, but it appears we have a difference in our explanations.
 
I'd imagine the 540 drive would have somewhat slower access times than the 8.4 gig drive. It'd be interesting to compare the difference.
 
Of course there's always the question... why? That is why do want to stick a 540MB drive ahead of an 8.4GB drive? I'm sure there's some interesting reason.
 
Stone said:
Of course there's always the question... why? That is why do want to stick a 540MB drive ahead of an 8.4GB drive? I'm sure there's some interesting reason.
Click to expand...

Thanks for the clarification guys. Looks like I can remove the EZ-BIOS software on motherboards with LBA capability. One less piece of software to worry about.

I started putting these smaller drives in front of larger drives on all my 386 and 486 machines. I have a lot of 540 meg drives and I figure I'll just put them as the master and load them with DOS and Windows, leaving the larger drive to serve as the holder of my applications and data. Plus, it lets the smaller drive take the brunt of hard disk access. And it finds a home for all these smaller drives. In this case, the 540 meg drives were originally in the machines that now have the 8 gig drives and were purchased new, so these machines will still have "new" drives.

See you're wrong....quite honestly, sometimes there's no good reason to what I am doing. LOL!!!

While I understand the 540 meg is no doubt slower than the 8 gig driver, I doubt hard disk access time is really an issue with DOS programs, especially if you have loads of memory.

And as pointed out above, it is real hard to fill 8 gig using only DOS.

Thanks...Joe
 
Stone said:
No, you're wrong... I didn't say good -- I said interesting. And, although your reason is interesting... it's not good! :) :) :)
Click to expand...

Ha-ha! Well, you asked for it. :)

I have a follow-up question. I have been trying to find the storage addressing limit for Maxblast EZ-BIOS as well as the address limitations of a BIOS with LBA. I am thinking about stocking up on some large IDE drives (maybe 250 gig) and I want to find out which machines could handle something that large. I cannot find any info on how large a drive Maxblast (I have version 1.10) can handle.

I can find information on the storage limits for each Microsoft OS, but determining the limits of Maxblast and the motherboard BIOS is eluding me. If Maxblast (or other third party software) can access the 250 gig drive, the limitiations of the BIOS become less important.

Thanks...Joe
 
I think it comes down to this. If your BIOS supports Interrupt 13h Extensions you're good to go with drives over 8.4GB. If it doesn't, you're not. It's strictly a hardware issue -- software e.g., DDOs, won't make it work in this case. But, if you are able to flash your BIOS with an appropriate upgrade you'll be OK.
 
Stone said:
I think it comes down to this. If your BIOS supports Interrupt 13h Extensions you're good to go with drives over 8.4GB. If it doesn't, you're not. It's strictly a hardware issue -- software e.g., DDOs, won't make it work in this case. But, if you are able to flash your BIOS with an appropriate upgrade you'll be OK.
Click to expand...

I just did some searching and a little reading. If the BIOS supports Interrupt 13h Extensions, then I can have a drive up to 9.4 trillion gigabytes. A further reading of the Maxblast documentation states the following (summerized):

BIOS Requirements: BIOS dated before 1997 will not support drives greater than 8.4g. To obtain the full capacity of a drive greater than 8.4g, either (a) upgrade the BIOS, (b) install a BIOS enhancer card or (c) use the Maxblast software (v9.06 or newer).

So while the documentation doesn't say how large a drive Maxblast can handle, I am going to assume it can handle up to 9.4 trillion gigabytes.

Thanks...Joe
 
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After the Int 13h extensions were released, there was one more size limit to deal with, the 137GB limit imposed by 28-bit LBA. EZ-Drive 9.06 likely doesn't support 48-bit LBA which imposes a 144PB limit. For DOS machines, the MBR partition map is stored in a 32-bit value and limits total drive space to 2.2GB. That is what the big fuss is about with UEFI and its GUID Partition Table which has a much higher limit.

http://www.tldp.org/HOWTO/Large-Disk-HOWTO-4.html
http://web.inter.nl.net/hcc/J.Steunebrink/bioslim.htm (outdated)
http://homepage.ntlworld.com/jonathan.deboynepollard/FGA/os2-disc-and-volume-size-limits.html
 
njroadfan said:
For DOS machines, the MBR partition map is stored in a 32-bit value and limits total drive space to 2.2GB. That is what the big fuss is about with UEFI and its GUID Partition Table which has a much higher limit.
Click to expand...

The MBR 32-bit limit actually resulta in 2^32 sectors x 512 bytes per sector = 2 TB maximum sized partitions.
 
njroadfan said:
After the Int 13h extensions were released, there was one more size limit to deal with, the 137GB limit imposed by 28-bit LBA. EZ-Drive 9.06 likely doesn't support 48-bit LBA which imposes a 144PB limit. For DOS machines, the MBR partition map is stored in a 32-bit value and limits total drive space to 2.2GB. That is what the big fuss is about with UEFI and its GUID Partition Table which has a much higher limit.

http://www.tldp.org/HOWTO/Large-Disk-HOWTO-4.html
http://web.inter.nl.net/hcc/J.Steunebrink/bioslim.htm (outdated)
http://homepage.ntlworld.com/jonathan.deboynepollard/FGA/os2-disc-and-volume-size-limits.html
Click to expand...

Thanks, that will be some great reading. I will have to study it as they throw numbers around and it can get a little confusing unless you take it slow.

I will then have to see if I can determine which method is being used by the Maxblast version I use and which limit will be imposed. I am guessing at this point any drive under 137GB would probably be okay, but I will make no assumtions until I can determine exatly what Maxblast is doing.

Added Note: Usually you can find anything on the internet. However, I have come up empty looking for the Maxblast 9.06 limit. Unless there is something in a text file on the installation disk, the only way I guess I'll know is to try different size drives which exceed the various limits and see which drives I can access.

Thanks...Joe
 
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Just an update for those who care. I removed my 8GB drive and replaced it with a 160GB drive. I also removed the VLB caching controller (Buslogic KT-410AC) and replaced it with a non-caching VLB controller. I did this because the Bus Logic controller has it's own BIOS and I wanted to eliminate that as a variable.

I set the BIOS to auto-detect the HD and booted with the Maxblast disk. I installed EZ-BIOS and tried to reboot with a WIN98 floppy. During the boot process (before reading the floppy) I used the CNTL key to enter the EZ-BIOS display (this occurs right after EZ-BIOS has loaded and installed its extensions). I got the EZ-BIOS display but the system hung because it would appear EZ-BIOS was unable to display the number of cylinders on the HD.

I then rebooted with the Maxblast disk and removed EZ-BIOS. This leads me to believe EZ-BIOS is probably limited to, at most, 137GB. I am going to retry this experiment with a 20GB drive and if successful will probably buy a 120GB drive and see if it works.

Thanks...Joe
 
Well, I've done some reading on the topic of the size limitations of IDE drives based on hardware and/or
software. It can be VERY confusing and sometimes it seems the only way to know if a machine can access a
certain size drive is to try it.

Anyway, here's what I think I've found out...

Hardware/BIOS Limitiations:

1. Any machine without LBA or CHS translation capability is BIOS limited to around 504MB.

2. Any machine with BIOS CHS or LBA translation capability should be able to access up to 8064MB.

3. Any machine with extended INT 13h capability (and LBA) should be able to access up to 128GB.

4. Machines with a BIOS dated after 2001-2002 should be able to access up to 2TB.


Software Limitations:

1. DOS is limited to 8064MB.

2. Win95b and beyond can get to drives at least up to 128GB using full 28 bit LBA addressing.


Although I can find no proof, I am thinking since EZ-BIOS can get me past the 8GB limit, it's upper
limit is probably 128GB. The only way I can test this is to buy a 120GB disk and try it.

I have been looking to buy a couple IDE drives and I see three sizes which interest me; 120GB, 160GB and
250GB. If I understand correctly, once a machine is capable of going beyond the 128GB limit, it can
access either the 160GB or 250GB disk.

Does this sound right?

Thanks...Joe
 
Something to add: AWARDBIOS has a nasty little bug in machines made in 1998-2000 or so where hard drives above 32GB will crash the BIOS at worst, and prevent the rest of your drive space from being detected at best. I've seen BIOS patches floating around that fix this problem, but I've never tried them myself on my affected mainboard.
 
First a question...which is the real BIOS date. The date which comes up as the first line on the screen during boot, or the date which appears in the "box" during boot after the first "beep" - the box which contains info about the floppies, ports, etc. These two dates are usually different, sometimes by a couple years. For example, the P233 MMX I describe below has an AMIBIOS date of 8/28/1997 on the first line and a date of 7/15/1995 in the box.

I just received a couple new IDE drives - a 120GB and a 250GB. I only ordered one of each so I could
test different machines to see which machines were limited to 137GB and which could access more.

From my reading, it sounds like we are dealing with only a couple major size barriers for machines made
in the 1990s and early 2000s. There is the 528MB limit, the 8.4GB limit, the 137GB limit and the 2TB
limit.

I first tested these drives in a machine I knew could access both sizes and got the anticipated results
- both were cleanly detected.

The following tests were done by first removing all existing hard drives.

I tried installing the 120GB into a P90. When I tried to do an AUTO-IDE detect, the BIOS hung. I did
not try setting the parameters manually to some lower value (like using TYPE 1) so the machine could get
past the POST and I could install EZ-BIOS to see what would happen. That will be tested later. It did
AUTO-DETECT a 20GB drive.

I tried installing, one at a time, the 20GB and 120GB drives onto a P233 MMX which has LBA capability. The BIOS does AUTO-DETECT both but it does so with the same parameters as an 8.4GB drive: 16383 CYLS, 16
Heads and 63 Sectors. It shows the total capacility as 8.4GB for both drives (the same as the native
8.4GB drive which is already in the machine). The 8.4GB capacity is real as I tried to use FDISK from
Win98 to partition the drive and could only partition 8.4GB.

Interestingly, the above parameters are listed on the lable for both the 8.4GB and 20GB drive. How can
this be? There are no parameters listed on the 120GB drive label.

I ran a couple freeware utilities which show the P233 has extended 13h support. Yet it seems limited to
8.4GB.

More testing to come. But I am getting more confused each day.

Joe
 
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