In principle, you can go without following manipulations. Windows checks hard disks only at load and shutdown. So, if your computer is always turned on, you may merely switch off power supply of the hard disk and switch it on later when it is necessary. There is one shortcoming here. If you forget that your hard disk is switched off and try applying it, your computer will reset :). This may cause some troubles if the computer operates at the moment something resource-intensive. Do you want to provide safety? Keep reading.
Not to hang up your computer to no purpose after switching off the power supply, deinstall the respective hard disk from the system. Our task is to automatize this procedure (as well as the reverse procedure – definition after switching on) up to one click. Program devcon will help us. To avoid necessity of writing long routes, it’s sensible to place it in one of the folders registered in alternate PATH (for example, windows\system) after downloading it. Take into account that Windows will find it only after restart.
Open the notepad and write a short script that will check the presence of appropriate disk in the system. Depending on the result of this check-up, it will either delete existing disk or toggle on the absent one. The script looks as follows:
@echo off
if exist < drive letter > (devcon disable ) else (devcon enable )
The first line is necessary in order the command processor wouldn’t waist time on displaying the process run. In case your disk is partitioned to several logical drives you may indicate any of them. There are more difficulties with search and entering Hardware ID. You’ll have to speak with devcon a bit. Open the command line (for those who have forgotten - Start -> Programs -> Accessories ) and write the following:
devcon hwids =diskdrive
The program will display the list of units marked in the system and belonging to the class “hard disk”. You’ll define the unit necessary for you without problems I think. I got the following:
It’s easy to guess that we are interested in the information under the title “Hardware ID’s”. You can choose any of the three IDs; I took the shortest one: IDE\WDCxxxxxx. Relocate it to the script. To do that, click the icon in the upper left corner of the window and chose Edit -> Mark. Select with the mouse proper line and push Enter to copy it. Return to the notepad with the half-finished script and insert the failing parameters. This is my result:
@echo off
if exist F: (devcon disable IDE\WDC_WD400BB-32CAA0______________________16.06V16) else (devcon enable IDE\WDC_WD400BB-32CAA0______________________16.06V16)
Save the file as .cmd and locate it in a far folder. Make a shortcut in the desktop with established parameter "run minimized" (otherwise, a window of command line will arise every time). Now you can test the system’s workability.
First of all make sure that the disk doesn’t contain any system programmes or swap, hiberfil or something like that. Otherwise there is serious danger (I mean system data integrity) to hang up the Windows; moreover, the devcon will not be able to deinstall Windows hot-swap, it will demand restart. Perhaps there is sense to switch off caching for that hard disk, though I didn’t have any glitches here yet.
In case everything is in order, boot with the hard disk on. Wait till the system becomes stabilize, open “My computer”, and click the toggle switcher. Then click the shortcut (though precedence rule actually is not important, you may deinstall hard disk first, and switch off the power supply then). If everything is done correctly, the logical drive (or drives, if there are several of them) must disappear. Has it disappeared? My congratulations. You’ve done everything correctly :). If you want you may dismantle this hard disk and take it somewhere with you, and then mount it back, and all this without turning the computer off. Now we must test the second half of the script. Click the toggle switcher inversely, wait till the disks run up and click the same shortcut. Observe appearance of the drive in “My computer” again. Do you like this? :)
To finish with, I mention that all experiments described above have been made with Windows XP; I didn’t test availability in other operating systems.
P.S. In case of SCSI hard disks this modding is easier, since they have onboard support of hot swap. The only thing the script must do here, both after switching off and on of the power supply, is to prospect new devices; the rest will be done by controller. As a matter of fact, the script will consist of one command:
devcon rescan
P.P.S. You can change toggle switcher to relay controlled from COM-port… But this is for maniacs :).
Update: By all accounts, some controllers allow managing without devcon – hard disk is installed and deleted automatically. You may try this experiment.
Mortis
