Can a device driver be loaded manually

After the pc has booted to DOS, can a device driver be loaded manully if it is not specified to load in the Config.sys ? (e.g a USB CD driver)

Also How to use the IF statement in the system files (CONFIG.SYS & Autoexec.bat) ? e.g. If I need to load a second device driver only if the first one failed to load.

The short answer is no. You cannot load a device driver from the command line, mainly because they are not executable programs. DOS only contains native code to handle the hard disk, the floppy, the monitor and the keyboard. Any other hardware you add needs drivers to extend DOS functionality.  The config.sys file gets read early in the boot process, and the device drivers are loaded with DOS not after the fact.

As for using IF in the config file, I don't think so. Probably because the command processor hasn't even loaded yet. You can however section off your config file and create multiple configurations. How you would even test whether a driver loaded successfully is beyond my knowledge.

And finally, you can use an IF statement in the autoexec file.

Good luck.  

Thanks for the information.

But my problem still has not been resolved.

The problem is I specifed the following device drivers to load in the CONFIG.SYS and it works on most of the machines except some oldd ones such as Dell Latitude D600 and IBM NetVista M41 :-
         
     sbide.sys,  lgdvdrom.sys and USB_CD.SYS CPQ

On these 2 hardwares, it came to a halt or hanging when loading the USB driver. However, for any other hardware models, it was OK with the loading process.

The reason to include all these drivers is to cover any IDE E-IDE ATAPI and USB CD drive that may be attached to the system during the boot.

Is there a way to get around the odd onces ?

Thanks

The config.sys file is not run as an executable but rather is just a series of directives for the OS loader to use in configuring DOS. You do have the option of mutiple configurations within a single config.sys. Something like this:

[MENU]
menuitem=IDE, Load IDE Config
menuitem=USB, Load USB Config
menuitem=BOTH, Load IDE & USB Config
menucolor=7.1
menudefault=IDE,30

[COMMON]
put all your config statements here except for IDE and USB drivers

[IDE]
put the IDE driver here

[USB]
put the USB driver here

[BOTH]
put both the IDE and USB driver here

Now when the system is started, the user will get a menu and can choose which configuration to use.

Hope this helps
 

I'm trying to get an ATAPI Zip driver loaded on 2yr old machine that I use exclusively with MSDOS 7.1--but it just won't work.  

I downloaded Iomega's DOS drivers and extracted all the various ASPIxxxx.sys files, etc. of which I only really need the ASPIATAP.SYS for my ATAPI2 internal Zip.  There is BIOS support for Zip booting, and I added the following to config.sys on a boot floppy:  

DEVICEHIGH=ASPIATAP.SYS /E:IDE-ZIP

The machine boots up fine and shows all connected drives, saying the driver is successfully loaded, but it just won't access.  

Any idea what I'm doing wrong?  I've already tried using Iomega's Guest.exe in the autoexec.bat, but that pretty much did the same... said it was recognized, assigned letter E: to drive but no dice when trying to access.  I've spent hours researching & trying different things, so I'm finally stopping at the proverbial gas station for directions after stubbornly trying everything I could think of.  Iomega is no help at all; any info on DOS support is highly outdated.

I've formatted the brand new Zip disk to NTFS from my XP machine, BTW.  The MSDOS 7.1 shouldn't have any problems recognizing it.