File System Errors w/ NT and Linux

Jim asks: "I'm having severe problems with my Linux file system. I have a 6gb HD with a 1gb fat partition containing Windoze 95, a 2.5gb NTFS partition with NT workstation, and a 2.5gb partition containing Linux. I use NT's boot loader. I used the directions in the HOWTO docs to create a file from the Linux boot sector so I can load that with NT's boot loader. The problem is, as I switch back and forth between NT and Linux, I encounter severe file system corruption in Linux, and minor corruption in NT. I've already run a surface scan on the drive and no physical defects were detected. I was told by a colleague that Windows NT does not respect partition boundaries as well as it should and is corrupting the Linux partition. Does anyone know if this is true? If so, does anyone have a solution? Does anyone have an alternate explanation, or better yet: a solution?"

Re:Try GAG

[petrov]

I wouldn't recommend going with GAG if you are trying to debug a disk problem. GUIs are great and all, and it would be sweet if a new product was bug free, but I would go with a well tested program such as lilo. You want to rule out possibilities for the causes of the corruption. I recommend switching from the NT loader to lilo.

I would guess that it's not the NT loader at all, but other information that you haven't told us, such as are you mounting your NT partitions and running file access there (such as via locatedb)? I would not mount any non-ext2 partitions in linux until you discover the causes of the corruption.

--sam

Try GAG

[CristianoMonteiro]

Try GAG [arrakis.es], is an excelent GPL'ed graphical boot manager, we use it to succesfully dualboot WinNT/Linux.

Hard drive failing???

[DeathBunny]

I've dual booted NT 4 (and NT 2000) with Linux on several systems and never had corruption. So this is NOT normal behavior. Changing your boot loader (instead of using NT's boot loader or LILO) will probably not help. I usually use NT's boot loader for dual booting, because it's the easiest way to get both OS's set up.

On of the previous posters mentioned checking that both OS's are using the same address system on your HD. (LBA vers Cylinders, Heads, Sectors, etc)
This is a fantastic recommendation, and I wish I know how to check for certain what each OS is doing.

Another possibility is that your hard drive is failing. I know this is not something you *wanted* to hear, but it is possible. I once had a hard drive start exhibiting behavior very much like you are describing shortly after I installed OS/2 2.0 on one of my partitions. For a while I was certain that dual booting with OS/2 was my problem. I deleted my OS/2 partition, and about a week later the HD died completely. The moral of the story.... Sometimes HD's die *very* slowly and start out by doing wierd things that corrupt your filesystems.

MBR in middle of disk...?

[grain]

I read somewhere that NT stores a copy of the partition table, or the MBR (can't remember which), both at the physical beginning and physical middle of the disk.

I can't rememeber, however, if it just plops it down in the middle of whatever partition is there, or if it instead stores its stuff at the logical middle of the NT system partition....just thought this might jog someone's memory.

LBA vs. CHS

[hab136]

NT and Linux might not be using the same type of drive access.. LBA vs CHS.

LBA turns the hard drive into sequential blocks, 0..(some huge number).

In CHS, you specify [C]ylinder, [H]ead, [S]ector (like 1024,16,63).

If NT and Linux are using different schemes, it'll work /most/ of the time, but you will experience random, bizarre corruption, as you are. It can happen even with one OS if you switch machines or BIOSes.

Check your BIOS to see which way it is (386's usually CHS, P5+ usually LBA), then make sure /both/ OSes are respecting the way it's laid out. On large (>8 gig) drives, either OS will sometimes use LBA regardless of the BIOS (>2 gig /should/ use LBA). You may need to reinstall one OS or the other (or both).

Preferable option is to use separate drives for each OS, but I realize this is not always an option.

Re:Hard drive failing???

[Zurk]

you might also consider using the SMART tools (d/l from freshmeat.net) to check if (your drive should be SMART compliant) your drive is failing.