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I’ve been back to using my Pismo PowerBook for production work for more than a week now, and while I’m enjoying its processor speed relative to the WallStreet ‘Book it replaced, the 20 GB hard drive Apple installed in it is a slug. This is especially noticeable when on the Internet, as the drive clunks and chatters away, copying data to the browser caches or email boxes. By comparison, the 10 GB hard drive in my recently deceased WallStreet PowerBook was significantly faster and emitted no head parking noises.

One workaround that I’ve known about for years, but had only ever casually experimented with, is using a RAM disk as the browser cache folder. Copying data to RAM is of course much faster than writing it to a hard drive.

A RAM disk is a piece of software that lets you use some extra RAM memory as a really fast hard disk. The disk will appear on your desktop just like any other hard disk, and you can copy files to it as you would to any physical media disk. The functional difference between a RAM disk and a physical media disk is that when you turn the power off to your Mac, or restart, the contents of the RAM disk are lost. (although most RAM disk programs, including the Mac OS feature, can be configured to automatically save the contents of the disk on shutdown or restart, but you can't count on this in the case of a crash or power failure).

Typical advantages of RAM disks include:
• Speed. Memory accesses are much faster than hard drive, floppy disk, or network accesses.
• RAM disks can provide safety as well. Some people use RAM disks as web browser cache volumes for this reason. If the disk somehow becomes corrupted, then the damage is localized to the RAM disk and doesn’t affect the system hard drive.
• Another advantage of RAM disks is small file overhead. In versions of the MacOS before 8.1, each file grows in increments of 1/65536 of the total hard drive size. In other words, even if a file is only a few characters long, on a one-gigabyte hard drive it will take up 16K. Since a RAM disk is typically a very small volume, the space lost to file allocation is minimized.
• Security. By using a RAM disk that is easily mounted and unmounted from the desktop, you can more easily isolate sensitive material. Note that using a RAM disk is no substitute for rigorous encryption; nevertheless, it can help prevent casual snoopers from digging through your material.

Typical disadvantages of RAM disks include:
• Many RAM disk programs do not save the contents of the RAM disk to a file on a (real) disk. This means that crashes or power failures cause the contents of the RAM disk to be lost. Some RAM disks that do save the contents do so only when the RAM disk is put away. ramBunctious has a write-through feature available that saves the contents as soon as the RAM disk changes.
• Many RAM disk programs require you to reboot before you can see the RAM disk. They also require you to reboot before you can reclaim the memory used by the RAM disk. ramBunctious uses the same memory that applications use, so it can create a RAM disk without rebooting, and you can reclaim memory used by the RAM disks instantly by putting them away.

To set up the Mac OS RAM disk, open the Memory Control Panel and click the RAM disk button on. Now, use the slider to allocate the desired percentage of your RAM for RAM disk use. RAM disk size will appear in the little window on the lower right. And unless you want your entire RAM disk set up to go “poof” when you shut the computer down, check the “Save On Shutdown” box as well. Close the control panel and restart the Mac in order to activate the RAM disk. You should now see a RAM disk icon on your desktop.

The downside with Apple’s built-in RAM disk feature in the Classic OS is that you have to restart the Mac after activating the RAM disk in the Memory Control Panel, as well as any time you want to resize the RAM disk. Back in the days before the Internet came to our neck of the woods, I used to run my PowerBook 5300 off a RAM disk most of the time, with a stripped down system and a few applications installed, and could go five or six hours sometimes without ever spinning up the hard drive.

My reason for running of a RAM disk wasn’t lower power consumption -- the 5300 was plugged in most of the time -- but rather to increase the 5300’s mediocre speed, and for the side benefit of silent computing. A PowerBook with the hard drive spun down is noiseless, except for the clicking of the keyboard.

However, the rigmarole required to set up in Mac OS RAM disk simply load browser cache files always seemed like too much trouble.

There was also the matter of my rarely having any RAM to spare on most of my Macs. However, the Pismo has 640 MB of RAM, which leaves me with vast amounts of unused memory capacity when booted from OS 9. Now, if it weren’t for the bother of setting up the RAM disk....

However, Apple’s built in RAM disk isn’t the only RAM disk solution. A couple of shareware programs Clarkwood Software’s ramBunctious and Mark Adams’ AppDisk will also do the trick, and with the happy facility of not requiring a reboot, either for disk creation/deletion, or for resizing. You can’t boot from them, but Macs since the New World ROM was introduced in 1999 have not been able to boot from RAM disks anyway.

I decided to check out both programs. The way they work is respectively fairly similar, but with some distinctions. AppDisk is simplicity itself. You just click on the program icon, open the Mac OS “Get Info” dialog, and set the preferred memory at whatever capacity what your RAM disk to have. Close the dialog box, double click to start up the program, and voila! -- you have a RAM disk.

ramBunctious is slightly more complicated, since it offers more features and options than AppDisk. You first start up the application. Then to create a RAM disk, choose “New RAM Disk” from the File menu and a dialog box will appear in which you can set the disk capacity and other parameters. When you close the dialog, your new RAM disk will appear on the Desktop or wherever else you specify. You can create as many RAM disks in ramBunctious as you like can have memory capacity for.

For my purposes, as a speed booster for Web browsing, both programs proved very satisfactory. Just open up your browser Preferences, find the cache settings window, and choose your new RAM disk as the cache folder.

I found that iCab, especially, showed a significant increase in speed with cache files directed to a RAM disk, and with hardly any hard drive activity. Netscape 7.0 was faster as well, but it seems to access the hard drive more intensely than iCab does, even with the cache going to a RAM disk. In either case, however, the speed improvement is substantial and worthwhile, and with my Pismo, the reduction in hard drive activity and noise is most welcome.

AppDisk 1.7.4 as been tested to work with Mac OS 8.6 and works with all versions of the Classic Mac OS, 7.0 and up. It seems to work fine on my Pismo under OS 9.1.

Since the battery charge life of a PowerBook is extended considerably if the hard disk is asleep, putting applications in small AppDisk RAM disks will cause them to not read from the disk every time they need to put up a window or do an operation. You can generally keep the hard disk asleep while using your program, until you need to save a document to the hard disk. AppDisk’s “launch on mount” feature makes this even easier, since you can make the AppDisk automatically run an application when you first start up the RAM disk. And it can also remove the RAM disk when you quit the application that was started up.

AppDisk has several options to automatically save a copy of the RAM disk contents onto your hard disk.

The big difference between AppDisk the built-in one in the Mac OS Memory control panel is that the AppDisk gets the memory for its disk from its own application memory. Most RAM disks take memory away from your total system memory when you start up, so you can’t get that memory back without restarting. To get the memory back with AppDisk, all you have to do is quit the AppDisk program or remove the RAM disk from your Desktop by dragging it to the Trash.

As long as you want to use the AppDisk, just leave the application running in the background. When you don’t want the disk any more or need memory for other applications, quit the AppDisk.

One use for AppDisk (or any RAM disk) is to put applications or documents you use often on the RAM disk. Then when you launch/open them, they will load immediately. If you have applications that load portions of themselves from disk while you are using them, they will speed up considerably on the RAM disk. Other uses include using the RAM disk as a temporary area to compress/uncompress files from archives with Stuffit or a Zip application. This will speed the cache/compress/uncompress process quite a bit if you are doing it to/from the RAM disk.

System requirements:
• AppDisk runs on any Mac with System 7.0 to 9.2.2

AppDisk is $15 shareware.

For more information or to download AppDisk, visit:
http://homepage.mac.com/mavsftwre/shareware02.html

ramBunctious 1.6.2 supports Mac OS 8.6 through Mac OS 9.2. If you need a version that works on older operating systems (or 68K machines), you can download ramBunctious 1.5. A Japanese version of ramBunctious is available.

ramBunctious features and Usage

• Several options let you customize for your desired balance of speed, security, safety, and versatility. For example, you can set it to write through to a file on a (real) disk for safety in the event of a crash. You can mount as many RAM disks as you wish (or as many as you have memory for) simultaneously. ramBunctious uses the same memory that applications use, so the memory used for each RAM disk is instantly available for other applications when the RAM disk is put away.

• Its menus, dialogs, and windows allow easy management of your RAM disks, whether you use a single RAM disk or multiple RAM disks with customized settings for each.

• When you create a RAM disk, you can specify initial settings. These settings can be adjusted later using the RAM disk’s settings window, and are discussed below.

• When you select “New RAM Disk...” from the File menu, a standard file dialog is presented:

• In addition to the standard controls to navigate and enter a RAM disk name, there are a few extra controls.

• You can choose the size of your RAM disk.

• If Startup Items Folder is selected, a folder called “Startup Items” will be created automatically on your new RAM disk. Any files (or aliases) in this folder will be automatically opened when the RAM disk is mounted. This powerful feature allows you to conveniently open documents or applications when you start your RAM disk.

• The Automount Volume feature lets you start up your computer with a RAM disk already mounted. It works by automatically placing an alias to the new file in the startup items folder of the System folder.

• The RAM-only volume checkbox lets you create a RAM disk without all the contents in an image file.

• All of these options can be adjusted after the RAM disk is created -- they exist here only for convenience while creating the RAM disk.

The RAM Disk menu lets you manipulate mounted RAM disks.
• When you select a RAM disk from the Put Away submenu, the selected RAM disk will be put away (unless it contains open files). There are three independent ways to put away RAM disks when you’re done with them: you can use this Put Away submenu; you can quit ramBunctious; finally, you can put away the volume from Finder.
• Each mounted RAM disk has an item in the RAM disk menu; a check mark next to it indicates that its window is open. To open a RAM disk’s window, select the item. If you select an item with a check mark already next to it, that window is brought to the front.

More ramBunctious features:
• ramBunctious has a “write-through” option. When activated, everything written to the RAM disk is saved to a (real) file. This means that the next time you mount the RAM disk, all the contents are still there. It also adds protection against data loss in the event of a crash.
• Write-through means that after information is written to the RAM disk, it is written “through” to the RAM disk image file. The benefit of write-through is that if your computer crashes, you won’t lose information: it’s written to a “real” file after it’s written to the RAM disk, making it safer than other RAM disks.
• The Automount Volume feature lets you start up your computer with a RAM disk already mounted. It works by automatically placing an alias to the RAM disk image file in the startup items folder of your startup disk’s System folder.

ramBunctious can be fully controlled by using AppleScript. For more information, see the ramBunctious dictionary (from the AppleScript Editor) and the example scripts included when you download ramBunctious.

While ramBunctious RAM disk cannot be used as a boot disk, the workaround if you have a Mac that supports booting from a RAM disk, is to set up a minimal Mac OS RAM disk to start up from, then use ramBunctious RAM disks for all the stuff you typically work on.

ramBunctious 2.0 is a RAM disk program for Macintosh computers using OS X and later, providing basic RAM disk functionality, including being able to read from and write to RAM disks originally created using ramBunctious 1.x on OS 9 or below.

OS X’s driver architecture is wholly different from OS 9 and below, so it was necessary to start over from scratch to implement a RAM disk suitable for OS X.

For a more detailed overview of RAM disks on OS X, especially compared to RAM disks on OS 9 and below, see our article discussing the issues.

If you’re used to ramBunctious 1.6.2, you may find yourself looking for features not yet available in ramBunctious 2. However, the primary goal was to make available an OS X RAM disk program as quickly as possible, and more features will be added to future releases as long as there’s a place for ramBunctious in the OS X marketplace. Multiple disks available simultaneously and real-time write-through are two examples of features that were sacrificed for now in order to release an OS X RAM disk program.

Clarkwood Software has posted an interesting article on issues pertaining to RAM disks in OS X here:
http://www.clarkwoodsoftware.com/rambunctious/RDOSX.html

ramBunctious is $25 demoware

For more information, visit:
http://www.clarkwoodsoftware.com/

Another application that supports RAM disks is Aladdin’s ShrinkWrap. More information here:
http://www.aladdinsys.com/shrinkwrap/

Charles W. Moore