Quickly rebooting between partitions
 

I am new to linux, as well as to pc hardware. I have 4 hard drives, one of which is being used right now. It has windows installed on a small partition, then linux installed (CentOS) on a small partition. There is also a 3 or 4 gb swap partition, whatever that is. The remaining 200 gigs is just empty non partitioned space because I may want to try out different distributions of linux.

I installed windows first, and now have linux isntalled but can't figure out how to get to windows, or even view that partition from linux. Also, what do I partition my 3 other drives so they can be shared among opperating systems?

I have been looking all over for a cd based program that will let me select a partition to boot from to start up, but all of them require installations, or are for dual boot off 2 hard drives or some other complicated stuff I don't even understand.

So if someone could spare a minute and help me easily swap between opperating systems that would be great. If you could explain what some of these partitions (like the recommeneded swap partition) even do, or how to access my windows partition and such from linux, that would be even better.

Thanks for your time!

PS. if there is another thread that answers this, my apologies, but I searched and found nothing as simple as this. Either they were very specific with a certain tool, or dual booting. I have also spent probably 3 to 4 hours doing research online and am still confused.

You already have a dual boot capability - sounds like Centos has hidden the menu from you. When you boot the machine, after the boot messages, try hitting the <Esc> key (every couple of seconds) until you see a boot menu.
You should be able to select Windoze from that (may be called "Other").

For partitions and such try this - the tldp site has lots of other doco; have a look around.
Searching here at LQ and google.com/linux will also find plenty.

This is Scottybaby, I was signed in as my friend and decided to create myself an account.

The problem is my boot order doesnt have partitions, it just has harddisks, I already messed around with that for an hour with no success. Are you talking about the bios boot order (cd, sata1, sata2, etc etc)or are you saying hit esc when CentOS is booting up? And what exactly does dual boot mean, does that mean windows is running on top of linux, or just that I have to operating systems installed on one hard disk.

Looking through that resource helped me understand the swap partition (but I dont know if I support the gbs, or 128 mbs) but I am confused on what to partition my 3 other harddisks that I wan shared over any opperating system. I understand to make it a primary partition, but then it gives me specific partition types.

Also how do I get to my windows operating files (partition) from linux.

One other thing:
I keep seeing "your boot partition must be contained within the first 1024 cylinders of the drive." I installed linux after I partitioned windows 50 gigs, wouldn't that mean my linux installment is after 1024 cylinders and wouldn't work..?

Thanks for the quick response!

To share files with both OS's, use FAT32, both Windows and Linux can read and write to these. NTFS can be read by Linux and is getting better at writing, but to be safe, use FAT32.

I haven't used CentOS, but I assume during installation that a bootloader was installed, GRUB or LILO. Do you not get a choice of which OS to load at boot? You might need to reinstall (or install) a bootloader.

O.K. - that reference was just that, not the bible. And now it's starting to show its age. If you have a recent PC (last 3-4 years) forget the 1024 cylinder problem.
Old news.

Dual booting means the ability to select from two (or more) systems to boot into - but only one runs. It's not a VM-type implementation.
I was talking about interupting the CentOS boot, not the BIOS boot selection.

I had a look at a CentOS box at work - it does use hiddenmenu. Open a terminal, and enter "su -" (needs the root password). Then "gedit /boot/grub/menu.lst". This is a full screen window editor.
Find the "hiddenmenu" line, and put a "#" character (no quotes) in column 1 - this comments out the line.

Reboot, and you will get the boot menu - with (hopefully) an option to boot windows.

Blobman;

I would recommend addressing the questions one at a time.

Here a few things that may help you get oriented:

1. The bios is only smart enough to look for boot code on drives--specifically sector 1 (aka the mbr). The bios knows nothing about partitions.
2. Once you tell the bios which drive goes first, it grabs the code in sector 1 and executes it in memory. That code is the first stage of what is called a "bootloader"
3. The bootloader has a configuration file somewhere---when you have more than one OS, the config file is where the necessary info goes.
4. Anything useful goes on partitions, which are simply "zones" on the hard disk. You must have at least one.
5. Once you are up and running, you can see what is in other partitions by first "mounting" the partition. Windows does this automatically, but will not recognize Linux partitions. Linux, however, can read NTFS partitions and is starting to have good write capability. Most, however, still recommend using a FAT32 partition for shared data. Another option is to keep all data on Linux partitions, and use a utility in Windows which makes them readable.

Once you have digested this and other help offered, then come back with more questions--one at time

Thanks for your help. I am actaully successfully booting between systems now, but am still confused if I set this up right.

There is a drive in lunx called sda2, then theres a drive next to it thats not called anything. Under properties it says LABEL=

When I mount that drive it says sda2 has already been mounted, and takes me to the sda2 drive. What exactly is going on, do you have any idea?

Like I said before, windows partition that windows made (whatever type that would be), linux partition, swap partition, blank space. So I am not sure if I should worry about this extra glitchy drive I have showing up.

I'm starting to crack the books to figure out how to even make my server run php mysql, and other stuff, but this little bug I haven't run across.

Thank you guys so much for your help,
Cameron

PS, is there any way to partition my harddrives without booting off the install cd, like in default built in tool with linux? I found a tool to format and unmount drives, but thats about it.