devicehigh(CMD) 19 June 1992 devicehigh(CMD) Name devicehigh - load device drivers into the upper memory area Syntax devicehigh=[drive:][path] filename [dd-parameters] To specify the minimum amount of memory that must be available before de- vicehigh attempts to load a device driver into the upper memory area, use the following syntax: devicehigh size=hexsize[drive:] [path]filename [dd-parameters] Description Loading a device driver into the upper memory area frees more bytes of conventional memory for other programs. Parameters [drive:][path]filename Specifies the location and name of the device driver you want to load into the upper memory area. dd-parameters Specifies any command-line information required by the de- vice driver. hexsize Specifies the minimum amount of memory (the number of bytes, in hexadecimal format) that must be available before devicehigh attempts to load a device driver into the upper memory area. You must use both size and hexsize, as shown in the second syntax line. Notes Using the dos=umb command To use the devicehigh command, you must also include the dos=umb command in your CONFIG.SYS file. If you do not specify this command, all device drivers are loaded into conventional memory, as if you had used the de- vice command. For more information about the umb switch, see the dos(CMD) command. Installing HIMEM.SYS and a UMB provider Before you can load a device driver into the upper memory area, you must use the device command once to install the HIMEM.SYS device driver and then again to install an upper-memory-block (UMB) provider. These com- mands must appear before the devicehigh command in your CONFIG.SYS file. If your computer has an 80386 or 80486 processor, you can use EMM386.EXE as the UMB provider. If your computer has a different processor, you must supply a different UMB provider. On some computers, you might even be able to use HIMEM.SYS itself as the UMB provider. Specifying a size limit If the device driver you specify on the devicehigh command line attempts to allocate more buffer space than is available in a block of the upper memory area, your system may lock up. You can try using the hexsize parameter to avoid this problem. In hexsize, indicate, in hexadecimal format, the amount of memory the device driver needs. To find this value for a particular device driver, load the driver into conventional memory and use the mem /debug command. This method is usually, but not always, effective. If no upper memory area is available If there is not enough upper memory area available to load the device driver you specified with the devicehigh command, MS-DOS will load it into conventional memory (as if you had used the device command). Example If you include the following commands in your CONFIG.SYS file, MS-DOS attempts to load a device driver named MYDRIV.SYS into the upper memory area of an 80386 computer: device=c:\dos\himem.sys dos=umb device=c:\dos\emm386.exe devicehigh=mydriv.sys Related commands For information about loading programs into the upper memory area, see the loadhigh(CMD) command. For information about loading device drivers into conventional memory, see the device(CMD) command.