‘Backup and Restore’

Peter Beaven and Mike Dabbs - 17 September 2008
speaking at the BerksFHS Computer Branch, Woodley

Information created on a PC is first stored on a hard disc. It might become corrupted or even lost completely when a laptop is ‘lost’ or a hard disc fails. Generally these discs are reliable but many people have had them fail; so Backup is necessary. It can be helpful to separate programs from data by creating separate partitions on a disc, or by adding an extra disc.

The backup files need to be created on a separate device. This can be:-

• Inside the computer on an extra disc
• Created inside the computer on a removable disc (Cd or DvD)
• Outside the computer on an external hard disc. These are often connected through the USB socket.
• On other external memory devices such as USB keys; these can be corrupted but are easy to use.
• On an external drive accessed over the internet, which means it is outside of the house.

A problem with using an extra hard drive for backup is that it is also liable to fail. The damage can be greatly reduced by using two drives in tandem, configured as RAID 1. This means that data is written to both drives in parallel and if one of the drives fails it can be replaced and the system automatically copies the data from the other. The disadvantage is that the capacity of the discs is halved but with decreasing prices of hardware this is less of a constraint.

Software

To copy data some sort of program is needed and where extra equipment is obtained it may come with appropriate software. Many programs will also write to optical discs but these devices are often used for selective backups where specialist programs are preferred. The main commercial suppliers are Roxio and Nero and copies of their programs can often be found on computer magazine discs. Nero 7 Essentials is on the May 2008 copy of PCW and back copies can be purchased for £5. The main program will create a disc and verify it to check it has been copied correctly. It also includes disc tools to check the integrity of discs.

Backup software

There are two main types of backup software that either copy files or make an exact image of the file, (mirror) which can be used to restore the operating system with other programs and also data files. The option to compress the backup is often available but mirroring usually produces large files.

Normally Windows XP does not include backup software but it can be downloaded. The following article on Backup includes links to the XP backup program and also to 3 free alternatives

http://www.pcw.co.uk/computeractive/features/2225088/back computer

Program options can include

• Full backup, which can include (or exclude) sub-directories
• Incremental backup; only copies files that have changed since LAST backup
• Differential backup; only copies files that have been altered since last FULL backup
• The backups can also be compressed and also include events - such as turning off the computer when finished.

Online storage

An extra form of backup is available over the internet, where files may be copied to the web space of your ISP or photographs stored at online at sites such as Flickr or Snapfish. Others may be allowed to share these. More general sites such as www.adrive.com or www.humyo.com offer 50 - 30 Gb of online storage. Transferring large amounts of data in this way could lead to restrictions or extra charges from your ISP.
Finally many genealogical sites offer the ability to save family history data, including photographs. Before using such sites you need to check who controls the data and whether you can restrict access in any way. Most such sites depend on subscription but it may be not clear what happens if this lapses

updated 14 Oct 2008