RAM

Random-access memory is one of those sticky issues when it comes to the PC. If you’re a workstation user, you’re probably used to working with scads of RAM. (Then again, most workstation users have someone else footing the bill, as the costs of that RAM can add up rather quickly.) In theory, it would be great to work with scads of RAM on a PC. Linux, like any 32-bit operating system, loves to work with as much RAM as possible.

In the real world, however, there are bills to pay, and the reality is that RAM is one of the most expensive parts of a PC, both upon initial purchase and if you ever want to upgrade. If you’re a workstation user, you’ll want to read through the following section, which explains RAM and the PC; if you’re a PC user and are comfortable in your knowledge of RAM, you can skip to the following section.

The PC and RAM

If you buy a PC these days and aren’t too attentive to details, you can easily end up with a PC that has 8 megabytes (MB) of RAM, as this is a popular figure with packages offered by the likes of CompUSA, Best Buy, and Computer City. In this day and age, 8MB isn’t a whole lot of memory, even when running Microsoft Windows, MS-DOS, and memory-hungry applications. It becomes even more confining when running Linux.

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WARNING:  This selection from the Slackware FAQ should illustrate problems associated with low memory:

Q: I can’t get anything to work at all! What’s the deal?

A: If you seem to suffer catastrophic failure (!), then check the file FILE_LIST on ftp.cdrom.com in /pub/linux/slackware against the contents of your disks and make sure you’re not missing any files.

Also, I’ve noticed that most of the reports of kernel panics and system hangs have come from people with 4MB. If you’re running into these types of problems I’d suggest forking over the $$$ for 4 more megs. I have 8 MB of RAM and never have crashes. (Well, only when I really push my luck.) If you don’t want to do that, then go through your /etc/rc.d/rc.* files and get rid of any daemons you don’t use, like cron, lpd, or selection.

If you’ve got 4MB and you’re getting “virtual memory exceeded in new” warnings, make sure you set up and activate a swap partition before running setup. If you’re really hard up on memory, you can boot a rootdisk using editroot instead of one of the usual boot kernels. This will mount the floppy in the root drive, and you’ll have to install from the other drive or from the hard drive. You will also not be able to create any kind of boot disk, so you’ll have to install LILO and take your chances. I suggest using this approach only if a swapfile will not work.

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Linux will boot and run on a PC with 4MB of RAM. However, you’ll be running into memory constraints very quickly, and chances are that you won’t be able to run the X Window System at all. In fact, 8MB is barely enough to run X and Linux. We used the combo on an 8MB machine, and the results weren’t too encouraging; in fact, we were strongly encouraged to ramp up to 16MB of RAM right away.

This is why we recommend you upgrade and buy as much RAM as you can afford. Before you do so, you should know how today’s PCs handle RAM and how you can buy it.

Almost every new PC supports Single Inline Memory Modules, or SIMMs. Additionally, almost every new PC has four SIMM slots on the motherboard, and most SIMMs are sold in multiples of two or four—1MB, 2MB, 4MB, or 8MB. The less memory on a SIMM, the cheaper the SIMM.

If you bought a PC with only 4MB of RAM, you probably ran into a situation where there were four 1MB SIMMs installed in the four motherboard slots. When you upgrade your PC’s RAM, these 1MB SIMMs will be relatively worthless, unless you bought a PC from a vendor that allows you to trade in old RAM when buying new RAM. (The trade-in price depends on the vendor. Typically, you’ll get a credit for half the price of the old RAM when trading it in, provided you bought a PC from a vendor that assembles its own PCs. We’ve dealt with some cloners that give you full credit on the old RAM when trading it in, provided the PC was bought within the last year.) The same would be true if you bought a system with 8MB of RAM, and the SIMM slots were filled with 2MB SIMMs.

The best-case scenario is if you have a PC and only half of the SIMM slots are filled; in our case, we lucked into purchasing an 8MB PC that had 4MB SIMMs. (Contrary to popular belief, not every PC needs all the SIMM slots filled in order to function properly.) In this case, we needed to buy two more 4MB SIMMs to stick in the empty slots, bringing the total to 16MB.

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NOTE:  Depending on the motherboard configuration, you may have to play with the SIMMs and their order in the slots. In the case of the 8MB PC with two more SIMMS added, we needed to stagger the SIMMs (old SIMM, new SIMM, old SIMM, new SIMM) before the system would recognize all 16MB of RAM. Normally this isn’t something that’s documented, so you might need to call the customer-support line for your PC manufacturer for advice when adding new SIMMs.

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NOTE:  EDO RAM is all the rage these days on new PCs. Basically, EDO RAM is faster than conventional RAM, but like everything else in the computer world, you pay a little extra for the privilege of speed.

Therefore, the issue becomes whether it’s worth the extra money to buy EDO RAM instead of conventional RAM (provided, of course, that the base price of a PC doesn’t already feature EDO RAM; several large computer companies, such as Dell, have already started featuring EDO RAM in all of their configurations). Our experience is that it’s worth the extra money. We’ve not run into a situation where the price of upgrading to EDO was too exorbitant, and the increase in performance was worth the slight increase in price.

Slackware Linux doesn’t care whether you’re using EDO RAM or conventional RAM.

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