How many OSes can I install? and Dissertation on Partitioning Part II (a work in progess)

[SUOrangeman]

As I await the arrival of Project K (see my rigs), I realize that I am presented with an excellent opportunity to slam as many Oses as possible onto my new system's main 40GB hard drive. Since I was also known to offer some advice about partitioning, documenting how I go about building this system will allow me to bring to you all the forever-promised update to my original Dissertation on Partitioning. AndyHui has been waiting for me to come through with this, and hopefully I won't disappoint.

I will be logging my adventures (and your comments) for a more-polished publishing here (and elsewhere?). 🙂

With that said, let's do some planning.

Here is what I have in my possession in terms of OSes (and some of the installation requirements):

[*]Windows 95/98/98SE/ME: FAT16 and FAT32 filesystems are native; require C: to be primary; C: either consumes entire drive or lies completely below first 7.8GB (1024th cylinder)
[*]Windows NT4 Workstation: FAT16 and NTFS native, same requirements on C:
[*]Windows 2000 Pro/XP Pro 😉: FAT16, FAT32, NTFS native; same requirements on C:
[*]Linux (Mandrake 8.0 through 8.1 beta 1, Debian 2.2, Progeny Debian 1.0, etc.): ext2 native (and many others including ext3, ReiserFS, JFS, XFS), \boot *should* probably be below 7.8GB and using the ext2 filesystem, *should* also have a separate swap partition
[*]BeOS 5.0 Personal Edition: BFS native (can read others), entire partition should be below 7.8GB
[*]FreeBSD: some BSD filesystem native, requires primary partition cut up into slices (at least / and swap)
[*]Solaris for i386: some Solaris filesystem, probably requires primary partition cut up into slices (at least / and swap)
[*]AtheOS: ???
[*]Darwin for i386: ???
[*]PetrOS: ??? (I only have the demo though)
[*]QNX Realtime Platform: ???
[*]FreeDOS: FAT16 and FAT32 native?, will it coexist with Windows?

Right now, I'm planning on Win2K as my main OS, with WinME (hey, I was an official beta tester), WinXP, the latest Mandrake, BeOS, FreeBSD, and QNX. I'' try others, but I've never attempted to install them or I don't expect them to work at all. Here's my partition idea for the moment:

1.5GB Primary: FreeBSD
1.0GB Primary: ??? (will try Solaris)
1.0GB Primary: FAT16 for booting Windows OSes, common temp and swap/page file space, FreeDOS?
36.5GB Extended
...?1.0GB? QNX
...?0.5GB? AtheOS
...?0.5GB? Darwin
...?1.0GB? PetrOS
...1.0GB BeOS
...50MB Linux \boot
...----7.8GB/1024th cylinder boundary---
...4.0GB NTFS Win2K
...4.0GB NTFS WinXP
...2.0GB NTFS Personal Files
...2.0GB FAT32 WinME
...X.XGB FAT32 General Use
...2.0GB ReiserFS Linux \
...0.5GB ReiserFS Linux \home (might also share with FreeBSD)
...100MB Linux swap

I'm thinking that I will install OSes I've never used before first (FreeBSD, Solaris, WinXP, others) just to see if they'll fly. I realize that I may have to temporarily install Win98/ME just to get some of those others up and running. With any luck, I'll try to still use the NT Loader as my primary boot sector, even though it will be buried a few GB into the drive. Additionally, system performance is not being addresses at this time.

OK. Now it is your turn. 🙂

1. What information above (particularly concerning the OSes and what I see as their requirements) is incorrect? I'd like to fix it now before I get in over my head.

2. What do you think about the partitioning scheme? I don't have a concrete method of choosing the partitions sizes as I did. I'm comfortable with my size selections fot Windows and Linux, but I'm just taking a guess for everything else/

3. What am I missing?

Thanks in advance.

-SUO, the AT Partitioning Crusader 😛

 

[SUOrangeman]

I see one thing I've forgotten already. 🙂

Why is that 1024th cylinder (or 7.8GB into the hard drive) important for booting?

Taken verbatim from an MS KnowledgeBase article, ...

"During the bootstrap process, the only mechanism available to Windows NT (or any other operating system) to access the drive is a set of functions in the BIOS known as Interrupt 13 (INT13). The INT13 functions allow low-level code to read from and write to the drive by addressing a specific sector on the drive. When the INT13 architecture was developed back in the early 1980s, the possibility of multi-gigabyte hard disks was not taken into consideration. The INT13 functions define 24 bits to describe a sector on the hard disk. This breaks down to a maximum of 256 heads (or sides), 1024 cylinders, and 63 sectors. With these numbers, only 256*1024*63 (or 16,515,072) sectors can be used with INT13 functions. At a standard 512 bytes per sector, this is 8,455,716,864 bytes, or approximately 7.8 GB. Note that for most modern drives, the computer's BIOS must support some form of sector translation for the BIOS functions to address the first 7.8 GB of disk space. The BIOS in virtually all modern computers supports "Logical Block Addressing," which allows INT13 functions to address the first 7.8 GB of drive space independent of the drive's physical geometry.

The INT13 functions are the only means available to the operating system to gain access to the drive and system partition until the operating system loads additional drivers that allow it to gain access to the drive without going through INT13."

Microsoft goes on to claim that their OSes after Windows 95 OSR 2 are not affected by the 1024-cylinder boot limitation.

In the same article, MS kindly explains the difference betwwen decimal mega/gigabytes (what hard drive manufacturers user) and binary mega/gigabytes (what operating systems use). Here lies the reason why a 20GB drive may show up as 18GB or so once you've got it up and running in your system.

"Note that file system limitations and hardware limitations exist independently of each other, and the most restrictive of the two is the determining factor in the maximum partition size. Another factor to consider when you are troubleshooting partitioning problems is that hard disk manufacturers often use "decimal megabytes" (1 megabyte = 1,000,000 bytes), whereas Windows NT uses "binary megabytes" (1 megabytes = 1,048,576 bytes). Using both definitions of a megabyte in calculations can often account for "lost" disk space. Also, this article assumes a sector size of 512 bytes in all calculations. Although a 512-byte sector has become a de facto industry standard, it is possible that disk manufacturers could produce drives with a different sector size. This would result in a corresponding change in partition limits. Partitions are based on cylinder, head, and sector calculations, not on byte calculations. Therefore, a change in bytes per sector causes a change in bytes per partition."

-SUO