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COMPUTER BITS BY JENNIFER BONNITCHA Hard disc failure: what to do when disaster strikes "Hello, is that Support? I'm having a problem with my computer. Something about a no-longer existent directory in WordPerfect not able to be read. I also get a message telling me there is a general failure reading drive C. What's the problem?" All hard discs fail eventually. Most can be expected to last for many years, however some will fail after only a few month's use for various reasons such as power spikes, faulty controller card, poor maintenance, the current bogey man - the virus, and just plain bad luck. Nothing can destroy one's faith in technology faster than the news that the last year or more of work has been lost. Be sure that your data is secure by making backups and keeping them in a safe place. The more diligent among you will more than likely have a backup procedure already in place. If you don't, consider implementing one immediately. Although any system can be "fixed" , the technician's idea of fixed and your idea of fixed will usually be totally opposite. You can replace any part of the computer and thus "fix" a problem - unfortunately you can't always keep any data stored on the computer. Recovering lost or damaged data is almost an art as it can be very time-consuming, difficult and in some situations, nigh on impossible. You can put it off until tomorrow, next week or next month but if you do, eventually you will lose valuable data and realise the folly of your ways. 88 SILICON CHIP Take the case of a very busy public relations company. Even though they backed up their data regularly to disc, this did not include their spreadsheet data since they "hadn't gotten around to it". Hard disc problems surfaced and there was no backup to save them endless hours of work (and dollars). BACKUP!! BACKUP!! BACKUP!! BACKUP!! So let's look at the current backup options and ways of decreasing the anguish caused by a hard disc crash. When to backup All users should have a plan for regular backups of data. Perform the backups at an interval suitable to the amount of activity on the system. Some users will find that daily backups are required (especially with ac- counting systems, etc) while others will find that a weekly arrangement is more suitable. Using your backup system to its full advantage, make a complete backup of your computer once a year, including all program and data files . This way, you will be able to quickly rebuild your hard disc structure. If you add or delete applications from your computer, perform the entire system backup again. Make a point of taking monthly backups of all data directories. Lastly, make a backup of your most popular applications on a weekly basis. This may seem like a lot of time and effort, particularly if you use floppy discs to backup. However, it is nothing compared to losing months of accumulated work. How then to stay out of trouble? How to backup Backups ,should always be performed to a removable medium. Don't be lulled into a false sense of security if your word processing system has backup options for timed backups (like WordPerfect) or creates "backup" files i(like WordStar and MS Word). Thes~ are in fact either temporary backtips of the current file which are deleted when the program is exited norm~lly (WordPerfect), or. an older version of the current file (WordStar, MS Word). When performed to a removable medium, you have fewer worries if the computer is stolen, a fire breaks out, the office sprinklers are accidentally activated, or the desk holding your computer collapses, etc. Backups should be performed on That's fine, so long as you don't have a faulty DMA chip. Many of the diagnostic utilities will check the DMA chip and thus report whether your computer can reliably support these fast backups. The humble DOS backup and a large pile of diskettes is the only way for a large number of computer users. If you take the time to explore the command, you will find that, apart from increased operator interaction and the number of diskettes, it can perform just as well as the tape backup. Using DOS backup For most users, backing up the hard disc involves copying the hard disc files onto one or more floppy discs using the DOS Backup command. By using the parameters shown here, the entire hard disc contents will be backed up. the chosen media on a rotating basis. If using a weekly tape backup system, a set of three tapes should suffice. A daily backup system would require five tapes. When restoring data, problems can occasionally arise with the tape backup itself. If you use the same tape each time, you can go no further - if you use several tapes you can at least recover some data rather than nothing at all. Try to think of every possible problem and plan your backup system accordingly. Thero is little point having a wonderful backup system in place if the tapes/ diskettes are stored right next to the computer. Fire, flood and thieves are not selective. Tape backup This is a reliable and effective method of preserving data. You should never have to lose more than one day's work under normal circumstances. Investigate thoroughly the tape backup system you fancy - it should be easy to use and as bulletproof as possible. Use the system regularly and try restoring data on a semiregular basis to satisfy yourself that it is working reliably. Bernoulli box Provided you use the Bernoulli box cartridge in this instance for archiving purposes alone, you should have no problems. Although it provides a convenient removable storage medium and has performance similar to a hard disc, the cartridges do wear out when continually used as a hard disc substitute. Thus, the reliability of the device as both a "hard disc" and backup medium should be viewed with caution. Floppy discs The time-honoured method of backing up hard disc data is the humble diskette. With backup programs like DS Backup, Fastback etc, you can squeeze your data so it takes much less space than the traditional DOS backup. However, the quality of the backup depends on several factors. First, this style of program typically uses Direct Memory Access (DMA) to transfer the data. DMA is the process of using chips inside the computer to send data to and from memory without using the CPU. The backup program can be sending data to the diskette while it talks about readying another diskette, so the computer is literally doing two things at the same time. Data is always on the move and so the backup process just flows along. The Backup command copies one or more hard disc files to diskette in a special format that allows a single file to occupy more than one diskette. Files copied with this command may only be used again once they have been processed using the DOS Restore command. The general syntax of the Backup command is as follows: BACKUP [d:][path][filename][.ext) [d:) [IS] [JM) [/D:date) [/T:time) [/L] [d:] [filename) Backup, like many DOS commands, refers to both the source and destination file(s). The parameters or switches, which may be entered in any order, have the following meaning: d: this is the disc drive. Drive specifications differ between DOS 2.x and 3.x: DOS 2.x - unless the computer has a second hard disc, the first drive specification is C. If the system has only one diskette drive, the second drive is A. Note that the second drive specification must be used in this command. DOS 3.x - source and target drives may be of any type; ie, diskette to diskette, diskette to hard disc, hard disc to diskette etc. Path designates a specific directory in the directory hierarchy where the file or files may be found . If no directory is specified, the current directory is assumed. Filename can be used to specify single files or global file characters. If the filename and extension parameters are omitted, the entire directory is copied. Ext specifies the filename extension and may be a global character. /S is a switch. Osing this switch, JANUARY 1991 89 You may think that your hard disc will never crash but rest assured that, sooner or later, it definitely will. Backing up can save you time & dollars. filename, Backup places a file called Backup.Log in the root directory of the disc containing the files being backed up. The log file contains a record for each file processed and identifies the diskette number of the backup-up file. If the backup log file already exists, Backup appends the current entry to the file. You can use the backup log file when you need to restore a particular file from a floppy disc, but you must specify which disc to restore so that the Restore command does not have to search for files. Backup now writes only two files on each backup diskette (Control.nnn and Backup.nnn, where nnn is the diskette backup sequence number) and for this reason, you cannot use an old version of the Restore command for files backed up with the DOS 3.3 command. DOS 3.3 Restore can, however, restore backup files generated by previous versions of the Backup command. Restore also no longer restores the COMMAND.COM or system files IBM.COM, IQ.COM, IBMDOS.COM and MSDOS.COM, thus enabling Restore to load files onto a hard disc without the often undesirable result of replacing the operating system files. The global characters referred to above are the wildcard characters * and ?. The ? character may replace any individual character; eg, SU?? would act on files called SUSI, SUZY, SUZE, etc; whereas SU* would act on files called SUSI, SUZY, SUZE, SUSAN, SUZANNE etc. Using the Restore command Backup also copies all subdirectories below the directory level specified in the path parameter. It's particularly useful if you have several sub-subdirectories. Thus, to backup the entire hard disc specify Backup C: \ A:/S /M is another switch. Following a full backup, this switch is useful since only those files that have been modified since the last backup are copied. Sometimes this is called an incremental backup. /A: DOS normally erases all the existing files on a backup diskette before commencing the new backup. Using the /A switch, you can add files to the diskette's existing files. This is often used in conjunction with the /M switch. 90 SILICON CHIP ID: the date switch enables you to backup only those files you modified on or after a certain date. For example, to backup only those files created since May 15, 1990, the parameter is /D:5-15-90. This switch is often used in conjunction with the /M switch. /f: similar to the date switch, it backs up only those files that you last modified at or after the specified time. /F: new to DOS 3.3, this switch causes the target diskette to be formatted if it is not already. For the switch to function, the Format command must be accessible by the current path since it is an external command. /L makes a backup log entry in the specified file. If you do not specify a This command restores files from a backup diskette to their original condition. Restore is used to place one or more files copied by the Backup command back onto the hard disc. If a file is accidentally destroyed, it may be recreated with this command if it has been copied onto a diskette using Backup. If a hard disc fails, this command restores the Backup copies after repair. Backup and Restore are also useful for transferring an entire subdirectory to another hard disc. The syntax of the Restore command for DOS 3.3 is as follows: RESTORE [d:](path] [filename] [.ext] [d:] [IS] [IP] [/B:date] [/ A:date] [/E:time] [/L:time](/Ml[/N] d: this specifies the first source drive and then the target drive. Note that the source drive must be included in the command. path: this is the directory to which the file or files are to be restored. If no path is specified, the current directory is assumed. filename: single files or global file characters may be specified. If the filename and e~tension parameters are omitted, all files in the directory are restored. ext specifies the filename extension and may be a global character. /S all subdirectories below the directory level specified in the path parameter are restored. IP when you include this parameter, DOS displays a prompt before restoring files that have been changed since the last backup, or files which have the Read Only attribute on. Use this switch when you want to perform a partial restoration from a complete backup of a directory or all hard disc files. For example: RESTORE A: C: \/SIP restores all files from Drive A to the hard disc Drive C, starting at the Root Directory, including subdirectories as appropriate and prompting for each file. /B:date restores only those files last modified on or before the specified date. /A:date restores only those files last modified on or after the specified date. /E:time restores only those files last modified on or at an earlier time than specified. /L:time restores only those files last modified on or at a later time than specified. /M restores only those files modified since the last backup. IN restores only those files that no longer exist on the target disc. Notes on Restore Restore was modified in DOS 3.3 so that it no longer restores COMMAND.COM and tpe system files IBMIO.SYS, IO.SYS, IBMDOS.SYS and MSDOS.SYS. This allows Restore to be used to load files onto a hard disc without overwriting these vital files. An interesting feature of the Restore command is its ability to recreate deleted subdirectories if you specify the IS switch. This is sometimes desirable when you restore an application and require certain data TRIM files, for example. Fortunately, this doesn't have any serious side-effects since the directory can be deleted if its restoration was unintentional. As with Backup, Restore returns exit codes upon completion which could be tested in a batch file using the Error level condition of the IF command: 0 Normal completion 1 No files were found to restore 3 Terminated by user 4 Terminated due to error If you need to restore data to a hard disc, generally start with the oldest discs first, particularly if partial backups have been made since the last full backup. This process adds to the hard disc all those backup files that have been created or modified since the last full backup. If the hard disc contains new files that are not on the backup diskettes, they are not erased since unlike Backup, Restore doesn't erase files on the disc before copying the backup files from the diskettes. The importance ofregular backups cannot be stressed strongly enough. You may think serious data loss will never happen to you - rest assured it definitely will! 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