Transcript continued

Memory systems
Unit objectives:
 Describe the function of memory and
differentiate among various types of
memory chips
 Differentiate among the various memory
packages
 Install RAM into a system while handling it
properly and meeting your PC’s installation
requirements
 Monitor memory usage
 Troubleshoot memory problems
Topic A





Topic A: Memory
Topic B: Memory packaging
Topic C: Memory installation
Topic D: Memory monitoring
Topic E: Memory troubleshooting
Memory
 RAM: random access memory
 Working area for data during
processing
 Need sufficient RAM for
– Performance
– Software support
 Quality of RAM is important
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
Larger memory units





Byte (B) = 8 bits
Kilobyte (KB) = 1024 bytes = 210 bytes
Megabyte (MB) = 1024 KB = 220 bytes
Gigabyte (GB) = 1024 MB = 230 bytes
Terabyte (TB) = 1024 GB = 240 bytes
Memory types
 Classify memory as:
– Volatile vs. non-volatile
– Static vs. dynamic
– Asynchronous vs. synchronous
Volatile vs. non-volatile memory
 Volatile: Loses contents without power
 Non-volatile: Keeps contents without power
Random access memory
RAM
CMOS
Volatile
Volatile
ROM
PROM
Non-volatile Read-only memory
Non-volatile Programmable read-only
Complementary metal oxide
semiconductor
memory
EPROM
Non-volatile Erasable programmable readonly memory
EEPROM
Non-volatile Electronically erasable
programmable read-only
memory
Flash
Non-volatile
Dynamic vs. static memory
 Dynamic (DRAM)
– Must be continually refreshed
– Inexpensive
– Physically small chips
 Static (SRAM)
–
–
–
–
Refreshing not required
More expensive
Larger
Faster
 Typical uses
– Main system memory: DRAM
– Cache memory and CMOS: SRAM
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
Memory access types
DRAM
Dynamic RAM
Older technology
FPM
Fast Page Mode
Improved over DRAM
VRAM
Video RAM
Dual port, optimized for
video
EDO
Extended Data Out
Improved over FPM
BEDO
Burst Extended Data Out Adds pipelining to EDO
SDR
SDRAM
Synchronous DRAM
Interleaving permits
overlapped requests
DRDRAM
Direct Rambus DRAM
16-bit memory bus and
two transfers per clock
cycle
continued
Memory access types, continued
DDR
SDRAM
Double Data Rate
Double transfer rate of SDR
SDRAM with two transfers per
clock cycle
DDR2
SDRAM
Double Data Rate 2
Double transfer rate of DDR
SDRAM with four transfers
per clock cycle
DDR3
SDRAM
Double Data Rate 3
Double transfer rate of DDR2
SDRAM with eight transfers
per clock cycle
Access time
 Latency
 Memory speed
– Nanoseconds vs. megahertz
 Overall speed
– Doesn’t include latency
 Bandwidth
Speed ratings
Activity A-1
Identifying memory characteristics
Topic B





Topic A: Memory
Topic B: Memory packaging
Topic C: Memory installation
Topic D: Memory monitoring
Topic E: Memory troubleshooting
Packaging
 Early PCs used individual DRAM chips
continued
Packaging, continued
 Package
– Small circuit board
– More commonly called a module
– Installed in slot
 Module contains
–
–
–
–
Memory chips
Connecting wires
Support chips
Pins or edge contacts
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 chips no longer has a 1:1
chip-to-bit limit
Package types





SIMM 30-pin – ADRAM
SIMM 72-pin – ADRAM
DIMM 168-pin – SDR SDRAM
DIMM 184-pin – DDR SDRAM
DIMM 240-pin
– DDR2
– DDR3
 RIMM
– 184-pin – 16-bit
– 232-pin – 32--bit
continued
Package types, continued
 MicroDIMM 144-pin
 SODIMM 144-pin – SDR SDRAM
 SODIMM 200-pin
– DDR
– DDR2
 SODIMM 204-pin – DDR3 SDRAM
Modules and chips
 PC100 and PC133 use SDRAM
 PC1600, PC2100, PC2700, and
PC3200 use DDR SDRAM
 PC2-3200, PC2-4200, PC2-5300,
PC2-6400, and PC28500 use DDR2
SDRAM
 PC3-6400, PC3-8500, PC3-10600,
and PC3-12800 use DDR3 SDRAM
Memory error recovery
 Parity — Detects an error
–
–
–
–
Even
Odd
Mark
Space
 ECC — Detects and corrects an error
 Desktop memory — No parity or ECC
 Server memory — Often includes
parity or ECC
Parity
8 chips,
no parity
9 chips,
supports
parity
Activity B-1
Comparing RAM packaging
Topic C





Topic A: Memory
Topic B: Memory packaging
Topic C: Memory installation
Topic D: Memory monitoring
Topic E: Memory troubleshooting
Memory installation considerations





Banking requirements
Proper handling techniques
Slot insertion techniques
Safe storage
BIOS configuration
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
Proper handling




Unplug computer before opening it
Dissipate static
Move around as little as possible
Always handle modules by their edges
Inserting memory modules
SIMM
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
DIMM
1. Spread retaining clips before insertion
2. Insert the module straight into the slot,
perpendicular to the motherboard
3. Push firmly until the retaining clips
snap into place on either side
Removing a module
SIMM
1. Gently release the retaining clips at
both ends of the module
2. Move the module to a 45-degree angle
if it doesn’t do so automatically
3. Remove the module
DIMM
1. Release the retaining clips on both
ends of the module
2. Remove the module by pulling it
straight up from the slot
CMOS configuration
 BIOS checks memory at boot
 Compares actual memory with CMOS
entry
 Follow prompt to update CMOS entry
Activity C-1
Adding memory to a desktop computer
Notebook memory
 Location varies from notebook to
notebook
 Refer to documentation
 Shut down notebook, unplug cord, and
remove battery
Shared video memory
 Main system memory shared with
video circuitry
– No dedicated video memory
 Reduces cost
 Uses less power; generates less heat
 Not all RAM is available to OS and
applications (does not show as
present)
 Slower than dedicated video memory
 Add more system memory to increase
performance
Activity C-2
Adding memory to a notebook computer
Memory in handheld computers
 Expandable memory, a feature of
more expensive handhelds
 Some use modules similar to those in
notebooks
 Most use memory cards similar to
those in digital cameras
 Have a slot for inserting a flash
memory card
 Consult the manual
Activity C-3
Adding memory to a handheld computer
Topic D





Topic A: Memory
Topic B: Memory packaging
Topic C: Memory installation
Topic D: Memory monitoring
Topic E: Memory troubleshooting
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
Performance tab indicators




CPU Usage
CPU Usage History
Memory (7/Vista)
Physical Memory Usage History
(7/Vista)
 PF Usage (XP/2000)
 Page File Usage History (XP/ 2000)
continued
Performance tab indicators, continued






System (7/Vista)
Totals (XP/2000)
Physical Memory
Commit Charge
Kernel Memory
Summary data
The Performance tab
Activity D-1
Monitoring memory usage
Virtual memory
Optimizing the page file
1. On boot partition by default
2. Determined by amount of RAM
3. Size automatically increases or
decreases for best performance
4. Can manually override the settings
5. Page file size range:
1. RAM × 1.5 to 3.0
2. System’s peak commit value
6. Can move file to different hard disk
Changing page file size
1. In Windows 7/Vista, click Start, right-click
Computer, and choose Properties
In Windows 2000 /XP, right-click My Computer and
choose Properties
2. In Windows 7/Vista, click Advanced system
settings
In Windows 2000/XP, activate the Advanced tab
3. In the Performance section, click Settings, and then
activate the Advanced tab
4 In the Virtual memory section, click Change
5 Clear Automatically manage paging file size for all
drives
6 Select Custom Size, and set the initial and
maximum size
Activity D-2
Changing the size of the Windows page file
Topic E





Topic A: Memory
Topic B: Memory packaging
Topic C: Memory installation
Topic D: Memory monitoring
Topic E: Memory troubleshooting
Memory testing
 POST not sufficient
 Use testing utility
– Memtest86 — Free, open source
– Microsoft Windows Memory
Diagnostic — Free, unsupported
 Boot from floppy or CD
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 Page Fault or
Exception errors
 Random crashes, corrupted data,
strange application behavior
Activity E-1
Troubleshooting memory
Unit summary
 Described the function of memory and
differentiated among various types of
memory chips
 Differentiated among the various memory
packages
 Installed RAM into a system while handling
it properly and meeting your PC’s
installation requirements
 Monitored memory usage
 Resolved memory problems