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2 Articles

Linux Fu: Reading Your Memory’s Memory

April 18, 2023 by 17 Comments

Linux users have a lot of software to be proud of. However, there is the occasional Windows program that does something you’d really like to do and it just won’t run. This is especially true of low-level system programs. If you want to poke around your CPU and memory, for example, there are tons of programs for that under Windows. There are a few for Linux, but they aren’t always as complete or handy. Recently, I had half the memory in my main desktop fail and I wanted to poke around in the system. In particular, I wanted to read the information encoded in the memory chips configuration EEPROM. Should be easy, right? You’d think.

Not Really Easy

One nice tool a lot of Windows users have is CPU-Z. Of course, it doesn’t run on Linux, but there is a really nice imitator called CPU-X. You can probably install it from your repositories. However, the GitHub page is a nice stop if for no other reason than to enjoy the user name [TheTumultuousUnicornOfDarkness]. The program has a gtk or an ncurses interface. You don’t need to run it as root, but if you press the “start daemon” button and authenticate, you can see some extra information, including a tab for memory.

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Solder Any Expansion Directly To Your Computer’s Memory

June 12, 2015 by 40 Comments

Heat up that iron, you’re going to want to try this one: [Hugatry] is adding hardware to his laptop by tapping into the i2c lines on the memory module. We love this because the penalty for borking memory during the soldering process is much lower than when soldering directly to a motherboard!

Until we watched the video after the break we hadn’t realized that memory modules usually have an i2c EEPROM on them. This is actually a standard called Serial Presence Detect which allows the BIOS to poll the memory and configure automatically. It seems ironic that we knew the Raspberry Pi HAT standard uses this same trick but didn’t know it was on computer memory as well.

Hardware-wise this provides an easy method of soldering your own equipment to the bus. From there it becomes a software hack. Linux, of course, makes this quite easy and that is demonstrated by [Hugatry] with an LM75 temperature sensors. We would like to hear from our Windows and OSX using readers on how the i2c bus can be accessed within those OS’s.

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