SuperLinux Encyclopedia - Memory

Note: There are some resources related to running on hardware without a MMU (Memory Managment Unit) in Embedded Computers.

Note: Some memory-related programming topics are in programing.

General Subject:

• Compressed RAM  "Memory Fragmentation" By C.Browne
• Linux ECC project (Memory Error Correction & C management/logging/etc)
• Flash RAM (for diskless-Linux systems):
  • M-Systems   Flash RAM with Linux support.
  • San Disk  Flash memory site.
  • CompactFlash Association  With links to other CompactFlash sites.
• Gmemusage: A Distinctive Memory Monitor   Feb'98 LG
• The SIG11 problem (Compiling Linux)
• MSI's DIMM memory compatibility list  [precise link broke]
• Memory Managment:
  • Memory Management  Has ">1 MB FAQ".
  • Geodesic Systems  $; Memory managment SW for C/C++.
  • mmalloc  High-performance memory management library.
• Memory Testing:
  • Sunsite has a program called "memtest" that tests memory. It creates a boot floopy. One boots from the floppy and a comprehensive memory test is performed.
• PC-100 memory:
  • CT article on PC-100 memory (very detailed)
  • MSI's FAQ on PC100 and SPD  [precise link broke]
  • Some modules (Memory Man?) are as much as 5 mm shorter than others (Corsair?). This might matter with some motherboards in some cases.
  • I read somewhere to be sure to get "GH" chips(or modules?), not "GL" or "G8".
• Secure Deletion of Data from Magnetic and Solid-State Memory (Doc by Peter Gutmann)
• Fast synchronized access to shared memory
• Swapping of memory to disk:
  • Swapping to NFS-mounted files (patches and info)

  •             SWAP FILE:
                dd if=/dev/zero of=SWAP-FILE-NAME bs=1024 count=71680
                sync
                mkswap SWAP-FILE-NAME 71680
                sync
                swapon SWAP-FILE-NAME
                
                SWAP PARTITION:
                Make the swap partition with fdisk or cfdisk.
                mkswap -c /dev/SWAP-PARTITION-NAME
                sync
                swapon /dev/SWAP-PARTITION-NAME
                
                BOTH:
                Add a line to your /etc/fstab file so "swapon" needn't be used after the next boot of the OS.
                Like this: /dev/hda3    swap    swap    defaults 0 0
          

• Ask Slashdot: Cache and RAM Limitations

Memory Tuning:

• Memory Tuning  Kernel document.
• Memory Tuning page

Large Memory:

• Howto use > 1.0 MB of memory
• Kernel patch to allow use of very large contiguous areas of memory  As need for some video HW.
• See "Memory Managment" on this page.

Small Memory:

• Small Memory mini-HOWTO  How to run Linux on a system with a small amount of memory.
• Small Kernel Project (supports Linux on 2 MB laptop; with links)
• TinyX (runs in small memory systems)
• Small memory tips 

RAM Disks:

• initrd.txt - how to use the RAM disk as an initial/temporary root filesystem.
• ramdisk.txt - short guide on how to set up and use the RAM disk.

Manufacturers and Sellers of memory:

• Azzo Computers / Ram Warehouse
• Corsair Microsystems (manufacturer of memory)
• Crucial Technology "A Division of Micron" (seller of memory)
• The Memory Man (manufacturer of memory)
• Platinum RAM (seller of memory?)

Memory detection problems: