Re: Boot Manager
- From: <Vanguard>
- Date: Sun, 3 Apr 2005 22:31:05 -0500
"Teilhard Knight" <teilhk@xxxxxxxxxxx> wrote in message news:3bbporF6jb27sU1@xxxxxxxxxxxxxxxxx
I have read all you have to say in this thread. I realize now I am damned because none of the solutions you give me are feasible. I need the boot manager for an old 486. Buying a new motherboard will cost more than the machine itself. Also, I do not think I will be able to find an ISA card which gives me access to the entire disk. Perhaps the only solution, as you say is to select the bootable OS whenever I want to boot it. Problem is I do not know whether I can boot into a logical partition (I'm running Linux).
The standard bootstrap program in the MBR will not boot to logical drives (in extended partitions). The bootstrap program can only select among the primary partitions listed in the partition table because the start of those partitions are known by the entries within the partition table. For extended partitions, only the start of the partition is known (as for primary partitions) but the start of the logical drive within that extended partition is not defined in the partition table.
The standard bootstrap program can only load the first sector of a partition (boot sector) for the primary partitions listed in the partition table, and it picks the one that is marked "active". Also, because the partition table only lists the partitions on that drive, you cannot use the standard bootstrap program to boot to operating systems residing in partitions on other drives. So, in your case, you will need to put each operating system into a primary partition on the first drive and in a primary partition. Note that some operating systems, like Windows NT, will let you boot using a primary partition on the first drive using the standard MBR bootstrap program but the OS loader files in that first-drive active primary partition can read files on a different drive in a different partition to continue loading the OS from there (see http://support.microsoft.com/?id=314470; Microsoft's terminology is backwards of what users would expect for the terms used for those partitions). Basically:
- BIOS completes POST and looks for sector 0 (MBR) on first physically detected hard drive.
- BIOS loads the program into memory from the first 460-bytes of the MBR (i.e., the bootstrap program) and starts it.
- Bootstrap program reads the partition table looking for a primary partition marked as "active". It loads sector 0 of that partition (boot sector) into memory and starts it. This starts loading the OS.
- The boot sector program for the OS can then start its own loader program and may even read files in other partitions or on other drives. This is a mini-boot manager contained wholly within the partition (i.e., it does not usurp the MBR bootstrap area).
I don't know what your *NIX operating system has for features regarding where it can be installed and if it can be spread across different partitions across different drives by using a loader or mini-boot manager program in its first booted partition. So while you might get stuck having to use something like PQboot or FDISK to change which is the active primary partition on the first drive, that may only determine where the loader files are located for the OS and the OS could possibly span onto a different partition or even a different drive.
-- ____________________________________________________________ ** Post your replies to the newsgroup - Share with others ** For e-mail Reply: remove "NIXTHIS", add "#VS811" to Subject. ____________________________________________________________
.
- References:
- Boot Manager
- From: Teilhard Knight
- Re: Boot Manager
- From: Vanguard
- Re: Boot Manager
- From: Teilhard Knight
- Re: Boot Manager
- From: Vanguard
- Re: Boot Manager
- From: Teilhard Knight
- Boot Manager
- Prev by Date: Re: My own special folder?
- Next by Date: NavExcel removal
- Previous by thread: Re: Boot Manager
- Next by thread: defrag
- Index(es):
Relevant Pages
|
