understanding the 1024 cylinder boundary

[chrisNova777]

https://www.partition-magic-manager.com/partition-magic/partition-magic-help/UnderstandingTheBIOS1024CylinderLimit.php

any partition size larger than 8GB has a potential problem... as far as DOS use goes...

If you have such a computer system and you use only DOS, neither the DOS FDISK utility nor PartitionMagic lets you see cylinders beyond the 1,024th cylinder or include them in any partition. Space beyond the 1,024th cylinder always remains invisible.

The BIOS 1024 cylinder limitation exists because the start and end cylinder values in the partition table (and some BIOSs) have a maximum value of 1024. Because some operating systems such as DOS 6.22 use the CHS (Cylinder, Head, and Sector) values to address sectors on the disk, they cannot access sectors beyond the 1024 cylinder. When you start your computer the BIOS boots the operating system using the CHS values to locate the first sector of the bootable partition. If the partition starts past the 1024 cylinder, the BIOS may not be able to boot it because it cannot address a cylinder number higher than 1024.

With PartitionMagic, you can safely partition any drive, regardless of the number of cylinders on the drive. In fact, to prevent you from performing partition operations that might cause problems, PartitionMagic is careful to observe the BIOS 1,024 cylinder limit on computer systems where one or more of the following applies:

1.The hard disk has a capacity 504 MB or more and the BIOS translation mode is set to Normal or CHS.
2. The hard disk has a capacity 504 MB or more and the BIOS was manufactured prior to 1994 (approximately).
3. The hard disk has a capacity 8 GB or more.

If you have such a computer system and you use only DOS, neither the DOS FDISK utility nor PartitionMagic lets you see cylinders beyond the 1,024th cylinder or include them in any partition. Space beyond the 1,024th cylinder always remains invisible.
Even if the BIOS 1,024 cylinder limit applies to your system, you can use PartitionMagic without difficulty. The only instance where you may encounter a problem is if all the following criteria apply:
4. You use DOS and another OS.
5. The other OS can "see" and use disk space past the first 1,024 cylinders on the disk.
6. You use PartitionMagic or the FDISK utility of the other OS to create a partition extending beyond the 1,024th cylinder.
7. You then run the DOS PartitionMagic executable.
When you run the DOS PartitionMagic executable, you may or may not be able to see the newly created partition that extends beyond the 1,024 cylinder limit. Even if you can see the partition, you cannot use the DOS PartitionMagic executable to perform any operations on that partition. This restriction applies to both primary and extended partitions that contain space beyond the 1,024th cylinder. If an extended partition exceeds the cylinder limit, you cannot perform operations on any one of the contained logical partitions, even if the logical partition itself does not extend past the 1,024th cylinder.
The disk map in the PartitionMagic main window displays an arrow indicator at the 1024 cylinder boundary (and the 2 GB boot boundary), so you can see where your partitions are located relative to the 1024 cylinder limit. Be sure that all OS partitions on a disk start prior to cylinder 1024. This ensures that you can boot the OS. Also, use caution when moving a bootable partition; if the partition is moved beyond cylinder 1024 it may no longer be bootable. To fix this problem you can move the partition below the 1024 cylinder marker.

Tips
1. If you use DOS, but your system has the INT 13 BIOS extensions, PartitionMagic lets you see cylinders past the normal 1,024 limit and perform operations on partitions extending beyond this boundary. https://en.wikipedia.org/wiki/INT_13H

[chrisNova777]

so basically if your installing any version of win9x or winME
best common practice would be to install winME first on FAT32 on the first primary MBR partition and make it 8GB or under then you can install windows XP using the rest of the drive, and add secondary drives + partitions for more FAT32 space later on after the dual boot of ME/XP is complete. but the WinXP partition remains Hidden to win9x, because win9x cant have more than one visible primary partition, and the filesystem for XP is NTFS not fat32. the process of installing XP after installing winME does this all by itself and adds a dual boot menu at the start to pick between the two os everytime you boot. i had to resize my fat32 partition.

i used partition magic 8.0 to help with this
https://archive.org/details/norton-partitionmagic-8.05
https://archive.org/details/powerquest-partitionmagic-8.0

[dawful]

Warning

The following may not be useful in any way!

I have some machines that can't decide how to behave, CHS or LBA. Sometimes it affects IDE drives, but most often this causes problems with USB drives. Especially, if you want to boot from them. The machines, I am describing, are much newer then the ones being discussed in this thread. And sometimes issues similar to mine, are actually the USB drive being accessed as a USB Zip drive (instead of a USB harddrive/memory stick).

The reason I mention it at all, is that I have occasionally used Grub2, to bypass buggy bios drive access. It has been a long time since I've haven't owned a machine, that only understands CHS, in a long time. I wonder if Grub2 can help bypass this issue, too (as long as it is "not" installed to a partition/or if it "is" installed to a the first partiton; being of a safe size/location). This won't help with the DOS6.22 problem. But Win95B, and newer, are DOS 7*. There are some hack to get Win95A on fat32, with more than 8Gb, but it comes with some limitations.

Grub2 will use your bios drivers, but can load its own drivers. Once, those drivers are loaded, booting options become more flexible. Another similar tool is Grub4Dos. You can remap your partitions, load a partition to ram, boot a floppy disk from a disk image on your harddrive, etc.

I don't know if either can bypass the 1024 limit (not buy experience), but I'm sure they would. I just haven't looked into it. And both Grub2/Grub4Dos are less then user friendly. Also, there isn't a good manual for either. Grub2 has better documentation; but some things you don't learn, without scavenging endless mailing lists and forums. Grub4Dos almost needs to be learned totally off of forum discussions. There is a boot tool called SuperGrub2, and by examining it's configuration files you can learn a lot.

Maybe this will be useful to someone.

I believe Grub2 needs a minimum of XP, to use it's included configuration tools. However, I have managed to use Dos and Win9x command prompt, to build a configuration (non-trivial for many). Grub4Dos, as you could guess, requires some kind of DOS.

If one has never used these before, I suggest playing around with a non-production system. Determine if it is worth the effort.