1. Memory systems Unit objectives Describe the function of memory and differentiate between different types of memory chips Differentiate between different memory packages Install RAM Monitor memory usage Test memory and troubleshoot memory problems

2. Topic A Topic A: Memory Topic B: Memory packaging Topic C: Memory installation Topic D: Memory monitoring Topic E: Memory troubleshooting

3. Memory RAM: random access memory Working area for data during processing Need sufficient RAM for –Performance –Software support Quality of RAM is important

4. Measuring memory Cells –Store a single bit of data –0 or 1 –Represents on/off or yes/no Measurement units –Bit –Nibble = 4 bits –Byte = 8 bits –Word = based on CPU 32-bit processor: 32-bit word 64-bit processor: 64-bit word

5. Larger memory units Byte (B) = 8 bits Kilobyte (KB) = 1024 bytes Megabyte (MB) = 1024 KB = 1,048,576 bytes Gigabyte (GB) = 1024 MB = 1,073,741,824 bytes Terabyte (TB) = 1024 GB = 1,099,511,627,776 bytes

6. Memory types Classify memory as: –Volatile vs. non-volatile –Static vs. dynamic –Asynchronous vs. synchronous

7. Volatile vs. non-volatile memory Volatile: Loses contents without power Non-volatile: Keeps contents without power RAMVolatile Random access memory CMOSVolatile Complementary metal oxide semiconductor ROMNon-volatile Read-only memory PROMNon-volatile Programmable read-only memory EPROMNon-volatile Erasable programmable read- only memory EEPROMNon-volatile Electronically erasable programmable read-only memory FlashNon-volatile

8. Dynamic vs. static memory Dynamic (DRAM) –Must be continually refreshed –Inexpensive –Small Static (SRAM) –Refreshing not required –More expensive –Larger –Faster Typical uses –Main system memory: DRAM –Cache memory and CMOS: SRAM

9. Asynchronous vs. synchronous Asynchronous –Not synchronized to system clock –Consistent time to access and read data Synchronous –Synchronized to system clock –Accesses data and returns in one or more clock cycles SDRAM faster than ADRAM

10. Memory access types DRAMDynamic RAMOlder technology FPMFast Page ModeImproved over DRAM VRAMVideo RAMDual port, optimized for video EDOExtended Data OutImproved over FPM BEDOBurst Extended Data OutAdds pipelining to EDO ADRAMAsynchronous DRAMNot synchronized to the system clock SDRAMSynchronous DRAMInterleaving permits overlapped requests DRDRAMDirect Rambus DRAM16-bit memory bus and two transfers per clock cycle continued

11. Memory access types, continued DDRDouble Data RateDouble transfer rate of SDRAM with two transfers per clock cycle DDR2Double Data Rate 264 bits per transfer to double DDR performance DDR3Double Data Rate 3Transfers data at a rate of 800– 1600 MHz

12. Access time Latency Memory speed –Nanoseconds vs. megahertz Overall speed –Doesn’t include latency –Doesn’t consider bus speed Bandwidth

13. Speed ratings

14. Activity A-1 Identifying memory characteristics

15. Topic B Topic A: Memory Topic B: Memory packaging Topic C: Memory installation Topic D: Memory monitoring Topic E: Memory troubleshooting

16. Packaging Early PCs used individual chips No more than 1 MB of memory continued

17. Packaging, continued Package –Small circuit board –Also called a module –Installed in slot Module contains –Memory chips –Connecting wires –Support chips –Pins or edge contacts

18. Single- and double-sided modules Early DRAM had chips on just one side Double memory by placing chips on both sides Double-sided modules have two rows of pins at bottom –Pins on front aren’t connected to pins on back Number of DRAM chips no longer corresponds to data being stored

19. Package types: desktops SIMM 30-pin SIMM 72-pin DIMM 100-pin DIMM 168-pin DIMM 184-pin DIMM 240-pin –DDR2 –DDR3 RIMM 184-pin

20. Package types: laptops MICRODIMM 144-pin SODIMM 144-pin SODIMM 200-pin –DDR –DDR2 SODIMM 204-pin

21. Memory error recovery Parity — Detects an error ECC — Detects and corrects an error Desktop memory — No parity or ECC Server memory — Often includes parity or ECC

22. Parity 9 chips, supports parity 8 chips, no parity

23. Activity B-1 Comparing RAM packaging

24. Topic C Topic A: Memory Topic B: Memory packaging Topic C: Memory installation Topic D: Memory monitoring Topic E: Memory troubleshooting

25. Memory installation considerations Banking requirements Proper handling techniques Slot insertion techniques Safe storage BIOS configuration

26. Banking requirements Install memory in groups called banks Bank might include 1, 2, or 4 slots Must fill every slot in a bank Might have to use same type and speed of memory in every slot Leave extra banks empty –With DRDRAM, install continuity modules Dual-channel architecture

27. Proper handling Unplug computer before opening it Ground yourself to computer’s chassis Move around as little as possible Lay module in static-safe packaging atop the computer’s power supply to safely discharge potential differences Always handle modules by their edges Never touch chips or contacts

28. Inserting memory modules 1.Insert module at 45-degree angle 2.While pushing into slot, move module to fully vertical or horizontal position Clips should engage automatically when module is fully seated

29. Removing a module 1.Gently release the retaining clips at both ends of the module 2.Move the module to a 45-degree angle 3.Remove the module

30. Storage Store in: –Original packaging –Static-safe bag Static-safe bag –Metal-coated plastic –Conductive –Transmits static charges slowly

31. CMOS configuration BIOS checks memory at boot Compares actual memory with CMOS entry Follow prompt to update CMOS entry

32. Activity C-1 Adding memory to a desktop computer

33. Notebook memory Location varies from notebook to notebook Refer to documentation Shut down notebook, unplug cord, and remove battery

34. Shared video memory Main system memory shared with video circuitry –No dedicated video memory Reduces cost Users less power; generates less heat Not all RAM is available to OS and applications Slower than dedicated video memory Add more system memory to increase performance

35. Activity C-2 Adding memory to a notebook computer

36. Memory in handheld computers Expandable memory, a feature of more expensive handhelds Some use modules similar to those in notebooks Others use memory cards similar to those in digital cameras Consult the manual

37. Activity C-3 Adding memory to a handheld computer

38. Topic D Topic A: Memory Topic B: Memory packaging Topic C: Memory installation Topic D: Memory monitoring Topic E: Memory troubleshooting

39. Task Manager Windows GUI utility Provides information on processes running Version available in all Windows OSs –Windows 9x/Me Program List –Windows NT/2000/XP/Vista/7 Task Manager Access: –Ctrl + Alt + Delete –Right-click empty space in the taskbar and choose Task Manager –Ctrl + Shift + Esc

40. Performance tab indicators CPU Usage CPU Usage History Memory (7/Vista) PF Usage (XP/2000) Physical Memory Usage History (7/Vista) Page File Usage History (XP/ 2000) continued

41. Performance tab indicators, continued System (7/Vista) Totals (XP/2000) Physical Memory Commit Charge Kernel Memory Summary data

42. The Performance tab

43. Activity D-1 Monitoring memory usage

44. Virtual memory

45. Optimizing the page file On boot partition by default Determined by amount of RAM Size automatically increases or decreases for best performance Can manually override the settings Page file size: –RAM × 1.5 –System’s peak commit value Can move file to different hard disk

46. Activity D-2 Changing the size of the Windows page file

47. Topic E Topic A: Memory Topic B: Memory packaging Topic C: Memory installation Topic D: Memory monitoring Topic E: Memory troubleshooting

48. Memory testing POST not sufficient Use testing utility –Memtest86 — Free, open source –Microsoft Windows Memory Diagnostic — Free, unsupported –DocMemory Diagnostic — Free, unsupported Boot from floppy or CD Full test suite can take many hours

49. Memory-related problems 201 BIOS error code at boot time Parity error message Computer randomly freezes (locks up) or crashes Wrong amount of memory reported by the BIOS Windows reports General Protection Fault, Page Fault, or Exception errors Random crashes, corrupted data, strange application behavior

50. Activity E-1 Troubleshooting memory

51. Unit summary Described the function of memory and differentiated between different types of memory chips Differentiated between different memory packages Installed RAM into a system while handling it properly and meeting your PC’s installation requirements Monitored memory usage Identified and resolved memory problems