This information page is provided as a service by CWC to assist our clients in understanding and implementing a data backup and archive plan. If you need additional assistance or have questions lease contact us directly at our Contacts Page.
Computer files can become
corrupted, are sometimes accidentally deleted or completely lost through a system failure. It is not a question
of if, but when. Losing files, much like losing your sanity, is very annoying. If you are running a business it
can be disastrous. Knowing how to backup and then doing so on a regular
basis is critical.
Backing Up
Update, May 2011 Since I retired Windows Vista and 7 have been released. Since I am still a Windows user and help non-profits with their systems I try to keep these help pages updated from time to time. When it comes to hints on how to keep your systems updated and secure the Windows Secrets website is the best. Check it out and sign up for their newsletters at http://windowssecrets.com/
On Backup for Windows 7 there are several good newsletters available at http://windowssecrets.com/top-story/build-a-complete-windows-7-safety-net/
For windows XP users see:
http://windowssecrets.com/top-story/preparing-windows-xp-for-the-long-haul/
http://windowssecrets.com/top-story/windows-xp-looking-back-looking-forward/
Backing up simply means to make a copy of your files and documents. Files can
be backed up to floppy disk, a Cd-Recorder (CD-R/RW, DVD),a tape drive, a Zip disk, a removable hard drive or another
computer over your local area network (LAN)..
If you have only a few documents or files to back up, copy them to a floppy disk. If you have a large number of
files, or are performing a full system backup checkout the links below to vendors of tape backup systems.
Backup Devices Vendors
Seagate, Travan small systems IDE tape drives
Sony, Large system SCSI tape drives
Iomega, Zip disks, CD-R, External hard drives
HP, Tape, DVD, CD-R Drives
Software Vendor
Runtime Software
Free backup and recovery software
Useful Information Sites
Backup Types
Full backup: All data on the selected drive or drives is backed up to the selected backup media. (tape, cd-rom etc.). A full backup requires a storage media capacity equal to or greater than the total size of all drives selected for backup. The advantage of a full backup is the simple and quick restoration of data from one source. If full backups are not performed at a regular interval, extensive changes or additions to your system and files can result in a loss of critical data.
Incremental backup: An incremental backup, backs up all files which have been changed or added since the last (incremental or full) backup. This backup type shortens the time required for each backup. The restoration time and difficulty is more extensive than that from a full or differential backup, as the selected files must be marked from backups made at different times. Incremental backups reset the files archive bit so each incremental is an addition to the last full backup. To restore ALL your files to the condition of the last incremental backup you must first restore the last full backup and then sequentially restore all incremental backups to the most recent one.
Differential backup, the recommended Daily Procedure: This backup type stores only the files that have been changed since the last full data backup. The archive bit is not reset. A differential backup requires more storage space on the media than an incremental backup but the files can be restored quicker and easier. For complete file or system restoration the last full backup is restored and then the most recent differential backup. As the files archive bit is not reset from the last full back each differential contains a snapshot of all files added or changed since the last full backup.
The biggest disadvantage of a differential backup is the lack of audit trails. If you have changed a data file several times during the period between your full and last differential backup only your most recent change is saved. The way around this limitation is the use of multiple backup media, that is do your full backup on one media and put it away, Perform each differential backup on a different media. The quantity of media and frequency of differential backups will depend how far back you want to restore changed files. If one week is sufficient you need one full backup media and a different media for each working day of the week. At the start of week two you write over the oldest differential set first thus rotating the media every week.
When the amount or size of changed files increases to the point where the daily differential backup is lengthy take your full backup and your last differential and set them aside as your archive set. Now add 2 media to your collection, do a full backup on one of them and start your daily rotation with the second new media and the remaining ones from the old set. ( This also helps you keep your media fresh as in the case of tape media they eventually wear out. )
RAID and Mirroring, is more a system than a backup procedure! Copies of or a mirror of your primary hard drive is stored redundantly on a second or several different media (usually other hard drives). In the past setting up a RAID or mirrored array was complex and expensive. With today's very cheep and fast hard drives, the built in mirroring with Windows NT or 2000 and vendors like Promise Technology who offer low cost RAID, IDE, controllers for Windows 9x, even a small network may consider these systems.The major advantage of data mirroring is when your primary drive fails the mirrored drive or drives take over immediately with no downtime or loss of data. In most offices a mirrored array can reduce your backup requirements to one full backup a week as the backup now becomes your secondary safety net.
Terms and Definitions
Media. What you backup to. Normally a cassette tape or cd-rom disk. Naturally the media is determined by the device.
Device. The hardware that holds the backup media. Normally a tape drive or cd-rom drive. Also see Raid and mirroring above.
Archive bit. If you right click any file in Windows Explorer you have an option to view the file properties (attributes) The Archive attribute refers to the computers understanding of the state of backup for that file. If the Archive box is checked the system believes that file is not backed up or has been changed since the last backup. If the box is unchecked it is believed to be backed up. See the Backup Types above to see how this information is used by your backup software.
Backup Software. Applications software that manages your backup device and media and allows you to select your backup type, frequency and usually schedules backups for a time when your system is idle or after hours.
Runtime Software
Free backup and recovery software
Barts Preinstalled Environment. "Bart's PE Builder helps you build a "BartPE" (Bart Preinstalled Environment) bootable Windows CD-Rom or DVD from the original Windows XP or Windows Server 2003 installation/setup CD, very suitable for PC maintenance tasks." Also lots of good information on system recovery in general.
Site updated 6/1/2009