XP Backup Utility

[mathare]

Up goes the Glos beacon :)

My boss is using XP's backup utility thingy to back up his PC to a new external hard drive he's just bought. He selected the option to back up everything, waited till it said it would take three and a half hours and left it. He says he went back to it this morning and it says it can't write to the disk for some reason.

He seems to think it could be to do with maximum file sizes (4GB for XP?) but I would have thought XP's backup utility would have compressed data and spanned multiple files.

How does it work and any idea what could be causing his error?

[mathare]

I'm taking down the Glos beacon as I think I have solved it :yikes:

We reckon his new external drive is formatted as FAT32 and if he reformats to NTFS all will be solved as the max file size issue goes away then.

[Win2Win]

You can format a large drive as FAT32, not really recommend, but possible.

[mathare]

But FAT32 only supports 4GB files as a maximum, that's the problem he's having. NTFS will solve all, of that I am confident.

[Win2Win]

FAT32 supports anything :doh My boot drive is 200GB's with FAT32

Use a disk manager to format it or Windows

[mathare]

FAT32 supports anything :doh My boot drive is 200GB's with FAT32But FAT32 as a file system has a limit on the maximum size of any one file, NTFS does not as far as I am aware

[Win2Win]

That's from the old days :) Software fiddles around it now, see if you can get a copy of Partition Magic, it's erm....magic.... :doh

[mathare]

That's from the old days :) Software fiddles around it now, see if you can get a copy of Partition Magic, it's erm....magic.... :dohNo point when you can just reformat as NTFS though. It's only on an external HDD. And it's not for me

[GlosRFC]

I'd go with Matt on this one - the biggest issues with FAT32 is that it lacks any of the security and compression abilities that NTFS has plus it has a finite number of clusters per partition. So while you can use software to increase the theoretical maximum size, all you're really doing is increasing the size of each individual cluster.

The maximum number of clusters that FAT32 can handle is approximately 268 million which would equate to a 1Terabyte hard disk. However there is a problem in that the file allocation table itself would be more than 1Gb. Each entry in the FAT uses 4kb to reference an individual cluster so you can work this out for yourself - 268 million entries * 4kb = a whole lot of disk space. And because your PC is referencing the file allocation table all the time, the OS can do one of two things; either store the entire 1Gb FAT into system memory or cache it to disk. Both these options will seriously degrade performance. To try to overcome this problem with larger HD's , FAT32 increases the cluster size in order to decrease the overall FAT size. So anything below 8Gb will be allocated 4kb clusters, an 8Gb drive wil have 8kb clusters, a 16Gb drive will have 16kb clusters, while any drive over this size will have 32kb clusters. This explains why FAT16-formatted drives had an upper partition limit of 2Gb.

Although FAT32-formatted drives no longer have this imposed limit, it's a fair assumption that that Keith's 200GB drive probably has a FAT of 20Mb instead of the 5Mb it should be!!

NTFS uses a different method of managing clusters which makes it much more efficient at using your HD space. Basically, if you have an older version of Windows, it operates in a similar way to FAT32 - as your HD increases in size, so do the clusters up to the maximum 32kb per cluster. But with newer versions of Windows (anything after Windows 2000), the maximum cluster size is 4kb regardless of HD size. So it uses less physical space to store the FAT and requires less memory. It also gives a theoretical maximum HD/partition size of 18,446,744,073,709,551,616 bytes - or 18 billion Gigabytes.

The other performance advantage of NTFS is that files that are physically smaller than the 4kb cluster size (including all the file attributes) are stored as part of the Master File Table itself rather than elsewhere on the HD. What this means is that you no longer have the situation where a 1kb file takes up 32kb of HD space - the entire 1kb of data is simply one record within the MFT. And because the MFT is permanently held in memory, it means these small files are instantly available without the need for your OS to read the HD.

Add to this the ability to compress drives safely, encryption of files/folders, and allocating personal disk space "quotas" and NTFS is a definite improvement.

The only reason for using FAT-based file systems with XP is if you're planning to run a dual-boot machine with an older operating system. Just remember that you can easily convert from FAT to NTFS but it's not so easy to revert back again.

Apologies for the failure with the beacon - bit tied up with a project at the moment - but I hope that was useful.

[GlosRFC]

Hahaha...just re-read that and sometimes I'm even capable of baffling myself when I ramble! So the simple answer is that formatting the drive as NTFS will get round the 4Gb file limit.

And the project I'm working on is a tourist guide site with a difference - instead of static images, each picture will feature some kind of animation. This example (http://www.pi.pwp.blueyonder.co.uk/test/gloucester2.html) will give you an idea of what I mean - watch for the ripples and seagulls.

[mathare]

Hahaha...just re-read that and sometimes I'm even capable of baffling myself when I ramble! So the simple answer is that formatting the drive as NTFS will get round the 4Gb file limit.I started to read the previous post and then thought better of it. Then I saw this one and it told me everything I needed to know. Thanks Glos :)