NAME

ramdctl, ramdstat − Ram disk control programs. 

SYNOPSIS

ramdctl [ −c size | −d ] [ −s ] unit [ unit ...  ]
ramdctl [ −q ]
ramdstat unit [ unit ...  ]

DESCRIPTION

RAM disks can be created and deleted at runtime with the ramdctl command.  A RAM disk is a reserved area of memory that can be treated just like a physical disk.  After it is created, it can have file systems installed and mounted.  Each RAM disk has a character device entry in /dev/rdsk, and a block device entry in /dev/dsk. 

It is recommended that RAM disks be allocated soon after the machine is booted.  As the system runs and memory is used and freed, it becomes fragmented. This makes the maximum contiguous block of memory smaller than when the system was first booted. 

To create a RAM disk, use the −c size (create) option.  Size is specified in bytes. 

The −d option deletes the passed units and frees the associated memory.  Note that all contents of the RAM disk are lost. 

The −q option queries which RAM disks have been configured and shows the status for each (see the −s option).  This is the default action if no arguments are specified. 

The −s option shows the status of the units:

size shows the number of bytes allocated for this unit. 

addr shows the starting memory address of this unit. 

flags shows the status of this unit: 1=device has been opened, 2=valid RAM disk. 

ramdstat is a synonym for ramdctl −s. 

The RAM disks are implemented via a special driver, therefore the maximum number of RAM disks is specified in the file /etc/conf/sdevice.d/ramd (see sdevice(4)).

SEE ALSO

ramd(7), sdevice(4), mkfs(1m), mount(1m). 

FILES

/dev/rdsk/ramdctl
Using minor number 255, this device is the control device, which should be used to create new RAM disk pseudo-devices. 

/dev/dsk/ramdn
The block-special device to be used for RAM disk unit n

/dev/rdsk/ramdn
The character-special (raw) device to be used for RAM disk unit n

/etc/conf/sdevice.d/ramd
Configuration file for RAM disks. 

DIAGNOSTICS

missing unit number
A unit number must be specified to indicate the RAM disk to affect. 

cannot get info on RAM disk on unit xxx: No such device
An invalid unit number was specified.

cannot open control device /dev/rdsk/ramdctl: Permission denied
The user should be super user to access /dev/rdsk/ramdctl.  /dev/rdsk/ramdctl must be writable to perform the necessary IOCTLs. 

ADDED VALUE

This entry, supplied by SunSoft, Inc., is an extension of UNIX System V. 
 

\*U  —  Version 1.0