Posts Tagged ‘RAM’

Super Simple Mac OS X RAM Disk Tool – rdmanage


I’ve ported my Linux RAM disk management simplification tool, rdmanage, to Mac OS X. Now you can enjoy all the benefits of zero seek times and upwards of 1GB/second sequential read speeds on an operating system that humans can use.┬áThe program still has to be launched from the command line, but I’ve kept it very, very simple – all you have to do is specify the size of the drive.


To create your RAM disk, open a Terminal window and navigate to where you’ve saved the program. At the command prompt, type:

$ ./rdmanage [size of disk in MB]

For example, to create a 500MB drive, you would type:

$ ./rdmanage 500

When your disk has been created, it will appear on your desktop and in Finder just like a USB or FireWire drive. When you’re done, eject the disk just like you would an external device.


You can either download the program by right clicking this link and pressing ‘Save As’/’Save Target As’, or if you’re already at a command prompt, use cURL:

$ curl -O

Once you’ve downloaded the file, you might have to specify it as executable:

$ chmod +x rdmanage

RAM Disk vs Hard Disk

A couple of days ago I posted a small program that I created to facilitate easy creation and management of RAM disks on a Linux system. At the time, I missed a prime opportunity to do some benchmarking:

Using a RAM disk, you gain a working folder with speed way far in excess of any hard disk or even solid state drive

Just how ‘way far in excess’ is the speed of a RAM disk than a traditional hard drive? Way far indeed, and here comes the proof:


Super Simple Linux RAM Disk Manager – rdmanage

I’m currently developing a piece of server software which needs to be able to create, modify, serve up and dispose of many temporary files many times every second. Because a great number of I/O operations will be occurring, the program requires very rapid disk access – ideally, it would run on a RAID array or a solid-state disk. Because the server I’m using doesn’t have either, I’m using RAM disks as a substitute.

RAM disks take a portion of your system RAM memory and make it available for storage by mounting it in your file system. Using a RAM disk, you gain a working folder with speed way far in excess of any hard disk or even solid state drive. The usual rules of RAM apply – this is volatile memory, so anything stored on a RAM disk will be erased when the power is cut – but it’s perfect for temporary file storage.

I’ve written a very simple program for Linux called ‘rdmanage’ to help create and manage RAM disks easily at the command line.


There are three modes of operation for this program – create a new RAM disk, create a RAM disk from an existing folder, and remove existing RAM disk. As promised, the program is very simple to operate:

To create a RAM Disk:

$ ./rdmanage create [size in mb]

For example, to create a 100MB RAM disk:

$ ./rdmanage create 100

To create RAM Disk from an existing folder:

$ ./rdmanage from /path/to/folder

For example, to create a RAM disk from the folder ‘/home/randymarsh/sim’:

$ ./rdmanage from /home/randymarsh/sim

To remove an existing RAM Disk:

$ ./rdmanage remove


– When using the ‘from folder’ mode, the maximum size of the folder is 512MB

– You will need root permissions to mount the RAM drive

– The ‘remove’ mode will commit the state of the RAM drive to disk in a folder called ‘ramdisk.contents’

– All operations will occur within the current working directory (i.e. the folder you’re presently in). To check which folder you’re in, type ‘pwd’ at the command prompt.

– Depending on how you download the program, you might have to set the file as executable:

$ chmod +x rdmanage

– If you want to check the status of your drive, it will be listed when you use the ‘df’ command

– For program help, type:

$ ./rdmanage help


You can download the program by right-clicking here and selecting ‘Save As’/’Save Target As’, or if you would prefer to download straight to your Linux machine from the command line, use wget:

$ wget

Hopefully this program can save you a bit of time creating and managing your RAM disks. Enjoy!