XPANDISK.SYS and XPANBOSS
Device Driver and Command

Michael J. Mefford
1988 No. 18 (Utilities)


Purpose: Permits varying the amount of expanded memory allocated to
a RAM disk without rebooting, when used on systems equipped with memory
that conforms to the Lotus/Intel/Microsoft specification.

Format: In CONFIG.SYS file:

DEVICE=XPANDISK.SYS [/Dn][/Sn][/En][/Mn][/An]

At DOS command prompt:

XPANBOSS [d:][/Dn][/Sn][/En][/Wn][/Rn][/Mn][/An]

Remarks: XPANDISK makes use of an Expanded Memory Manager. The
DEVICE=XPANDISK.SYS entry must, therefore, follow the DEVICE=EMM.SYS
(driver name will differ with manufacturer) line already in the
CONFIG.SYS file. XPANBOSS varies the parameters of the RAMdisk d:
created by XPANDISK. Note that while this does not require rebooting,
changing parameters other than /R (Read-Only) does reformat d:, whose
contents are thereby lost. A confirmation warning is given to allow
saving the RAMdisk files before the reformatting. The optional switch
parameters for XPANDISK.SYS and XPANBOSS.COM are as follows:

/Dn Disk size, variable from 16K to 32,768K; default 64K.
/Sn Sector size, 128, 256, or 512 bytes; default 265 bytes.
/En Number of RAMdisk root directory entries; default 64.
/Mn Minimizes RAMdisk size (to 16K); use when running
large spreadsheets or databases.
/An Expands RAMdisk to fill all extended memory.
/Wn Eliminates warning that changing RAMdisk
parameters loses contents; use in batch file operation.
/Rn Make RAMdisk read-only; use after loading possible
Trojan horse programs. RAMdisk d: may be returned
to read-write by entering d:XPANBOSS.

Note: DOS assigns the next available drive letter as d:. Be sure
that this does not cause a conflict if you are using a SUBST drive.

Note: XPANDISK and XPANBOSS allow the same parameter comments
permitted by the VDISK.SYS extended/conventional device driver. Thus,
for example, you could enter

DEVICE=XPANDISK.SYS /disk size=120K /sector=128

and DOS would understand this as

DEVICE=XPANDISK.SYS /D120/S128