Managing drive Letter Assignments on PC"s

by John S. Allen

(c) 1997, man S. Allen

Thanks to Mike Newcomb the the

Boston windows 95 User Group

for assistance

Repartitioning - problems and advantages | how PC"s allocate journey lettersReal-world examples | utilizing dummy journey lettersAvoiding or hiding major partitions | different uses for various drivesDealing v SCSI drives and also removable trays | Conclusions

Hard drive partitions show up to DOS and Windows 9x as separate drive letters, even if it is they are on the exact same drive or on separate drives. The only method to configure partitions used to be through the DOS FDISK utility, i beg your pardon destroys every the data ~ above the drive. Come repartition a drive, you had actually to ago up the data, operation FDISK and also then reclaim the data. This might take hours.

PowerQuest Partition Magic and also other similar utilties have the right to now create, resize and delete tough drive partitions simply, quickly and easily, and without ruining data, a capability which is extremely advantageous with today"s large-capacity tough drives.

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Repartitioning - problems and advantages

But every is no so simple! drive mapping of most PC"s is an extremely inflexible. Including a brand-new drive or partition often changes the drive letter for currently partitions.

This is a actual fly in the ointment. Once this happens, Windows software packages can not find all of the papers they must run. You can resolve this trouble laboriously, by reinstalling the software. There are utilities easily accessible which reconfigure software program without the need for a complete reinstallation. One such energy comes through MicroHelp Uninstaller 4.0 (and contained in Partition Magic v. 3.0). Another such utility is obtainable as freeware from pc magazine. Still, the procedure of reconfiguring is time-consuming -- and it is not always successful.

Problems with drive letter alters occur even with data files, since Windows OLE understands only absolute links, not relative links (which, for example, preserve every one of the web links in a brochure tree when that tree is relocated to a various drive).

Yet repartitioning is often really advantageous. The record Allocation Table in DOS and also Windows divides a partition right into a best of 65,536 allocation "clusters." through today"s large partitions, the cluster dimension must thrive quite huge to save the variety of clusters under 65,536. ~ above a 1 GB come 2 GB drive, each swarm is 32 kilobytes in size, so even a 1-byte document occupies 32 kilobytes of decaying space. Also with big files, any type of leftover space in the last cluster the document occupies is wasted.

This instance will improve over the next couple of years together the FAT-32 paper system in windows 9x becomes common. FAT-32 allows over 4 exchange rate clusters per partition. Home windows NT/2000 additionally uses one advanced document system, yet it is different. FAT-16 is the only format supported by every one of them. And smaller partitions space the means to save space. The very first time I used Partition Magic on my 1600 megabyte Maxtor drive, i recovered over 300 megabytes.

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You enjoy savings favor these too, yet you need to plan ahead to minimization the trouble of journey letter reallocations, and also I"ll present you how you can do this.

How PC"s allocate drive letters

Most PC"s map cd driver in this order:

1) Floppy cd driver A: and also (optionally) B:

2) The major partitions of principle drives in the order castle are connected to the drive controller, starting with journey C:

3) The major partitions of SCSI hard drives in the stimulate of their SCSI identifier

4) The logical drive(s) in the expanded partition that the C: drive

5) The reasonable drive(s) in the expanded partition that each extr hard drive, acquisition the cd driver in the very same order together in 1, 2 and also 3

6) Under windows 9x, primary and extended partitions of any kind of removable-media drive(s)

7) cd driver such together CD-ROM drives and removable-media cd driver not installed by the BIOS, in the bespeak they appear in CONFIG.SYS or as mentioned in the home windows 9x maker Manager

8) Network drives as mapped utilizing network software program or the home windows 9x machine Manager

There is some flexibility in hardware installation: as long as you have only one partition ~ above a drive, you can assign drive letter by connecting the drives to the computer"s primary and secondary IDE controllers, and also by setting jumpers to configure the cd driver on every controller together master and slave. The only adaptability through software, on the other hand, is with drives (typically, CD-ROM and network drives) that room not mounted through the BIOS.

Further information on journey letter assignments and partitioning is accessible on the Web:

MS-DOS and also Windows 95 drive letter assignments (Important - contains details on additional primary partitions and also other subject left out of the an introduction in this article)

Changing letter of CD-ROM journey in windows 95 | ms DOS partitioning summaryWindows NT drive letter assignmentsNovell technical support papers on journey mapping

Some real-world examples

Now let"s see exactly how drive assignments job-related out in practice.

Example 1: The BIOS of many PC"s assigns drive letters in ascending order start with C: because that the master drive top top the major controller, as displayed in the complying with table: