Study Lab for Chapter 7

Use the "Key Terms and Definitions" section of the lab to review terms used in this chapter. Try the "Practice Test" to check your comprehension of the chapter. Tackle the "Lab Exercises" to apply your knowledge.

Key Terms and Definitions

bank

Amount of memory that must be added to be recognized by the system.

CAS Latency

How quickly (in cycles) a memory module can switch to a new memory address.

COAST (Cache On A STick)

A removable cache module.

continuity module

Empty Rambus module that must be plugged into a Rambus RDRAM module socket not occupied by a memory module.

DDR SDRAM (Double-Data-Rate SDRAM)

Performs two memory accesses per clock cycle for double the throughput.

DDR266, DDR333, DDR400

Standard speeds (in MHz) for DDR SDRAM.

DIMM (Dual Inline Memory Module)

A memory module with different connectors on each side. Used for SDRAM (168-pin) and DDR SDRAM (184-pin). Current.

DRAM (Dynamic RAM)

Requires frequent recharges. Most RAM is a variation on DRAM.

dual-channel

Memory access type that treats two banks as a single bank. Requires two identical memory modules.

ECC (Error Correcting Code)

A type of memory that uses parity bits to correct memory. Requires motherboard/chipset support, and is used primarily on servers and high-end PCs. Enabled through system BIOS.

EDO (Extended Data Out)

A faster form of DRAM using overlapping memory addresses.

FPM (Fast Page Mode DRAM)

Standard DRAM type used on SIMMs.

L1 cache

Memory cache built into the CPU core . Defective L1 cache requires CPU replacement.

L2 cache

Memory cache that is on the motherboard in Pentium-class processors but is built into the processor with Pentium II or later processors.

L3 cache

Third-level memory cache. Very rare on PCs, but occasionally seen on servers.

memory chip

Holds one bit or more of memory space.

memory module

Memory device made up of memory chips, such as SIMM, DIMM, or Rambus RDRAM module.

multibit chip

A memory chip that holds more than one bit of memory. Multibit chips make high-capacity memory modules with relatively few chips possible.

non-parity

Memory that doesn't use parity checking, or a system on which parity checking is not available or is disabled.

ns (nanosecond)

One billionth of a second; the basic measurement used for memory. Smaller ns ratings indicate faster memory.

odd parity

Parity-check method in which the sum of the data bits and the parity bit adds up to an odd number. If an even number results, the system halts with a parity error.

overclocking

Running memory or other components at faster-than-normal speeds; can improve performance but cause system instability and overheating .

parity checking

System for detecting memory errors; uses a parity bit plus the data bits to create a checksum.

PC-66, PC-100, PC-133

Standard speeds (in MHz) for SDRAM.

PC800, PC1066

Standard speeds (in MHz) for RDRAM.

PC2100, PC2700, PC3200

Standard speeds (in MBps) for DDR SDRAM.

pipeline-burst cache

Surface-mounted cache chips used on late-model Pentium-class motherboards.

RAM (Random Access Memory)

Memory that can be written to and erased freely .

Rambus RDRAM Module

A memory module that uses Rambus DRAM. A single-channel module has 184 pins, whereas a dual-channel module has 232 pins. Current.

RDRAM (Rambus Direct RAM)

A narrow-channel memory type that is faster than SDRAM but much more expensive than (and about the same performance as) DDR SDRAM.

SDRAM (Synchronous DRAM)

Memory running in sync with processor bus.

SIMM (Single Inline Memory Module)

The earliest type of memory module. Available in 30-pin and 72-pin versions. Obsolete.

SIPP (Single Inline Pin Package)

A memory module similar to a 30-pin SIMM, but with sharp spikes for memory contacts. Obsolete.

SODIMM (Small Outline DIMM)

Compact version of DIMM for notebook computers. Current.

SRAM (Static RAM)

A form of RAM that uses electricity less often and is faster but bulkier and more expensive. Used for cache memory.

TAGRAM

A chip used as part of an SRAM cache chip installation.

Practice Test

1:	You are installing memory on a system with dual-channel memory support. One DDR DIMM memory module is already installed. To enable dual-channel memory, you should perform which of the following actions? (Choose one) Remove the module and install a dual-channel DIMM in its place. Install a second DIMM. Install a second DIMM identical to the original DIMM. Install two additional DIMMs.
2:	Which of the following is true about the relationship of ECC and parity checking? (Choose all correct answers) Both ECC and parity checking are standard features on all computer systems. ECC and parity checking require additional memory bits over those needed for data. Both can correct memory errors. ECC can correct memory errors, whereas parity checking halts the system if a parity error occurs.
3:	You have a memory module with chips on both sides. Which of the following is true about this module? (Choose one) The module must be a DIMM. The module must be a SIMM. The module could be either a DIMM or a SIMM. The module must be a Rambus RDRAM module.
4:	A 72-pin SIMM has the following designation: 2Mx36-70. Which of the following statements accurately describe this module? (Choose one) 8MB 70ns module with parity checking 8MB 70ns module without parity checking 16MB 36ns module with parity checking 2MB 70ns module with parity checking
5:	A 168-pin DIMM has the following designation: 32Mx72 100MHz CL2. Which of the following statements accurately describe this module? (Choose all that apply) The module is a 256MB module. The module is a 32MB module. The module is slower than a CL3 module. The module supports ECC.
6:	You need to replace a pair of 64MB 184-pin DIMMs with a 128MB DIMM that runs at 333MHz. Which of the following DIMM designations is the correct replacement? (Choose one) PC2100 PC2700 PC3200 PC1600
7:	The motherboard has memory sockets with three connectors for memory: a narrow one at one end, a wider connector in the middle, and the widest connector at the opposite end from the narrow connector. Which type of memory module is this motherboard designed to use? (Choose one) 168-pin Rambus RDRAM module 184-pin DIMM 72-pin SIMM 168-pin DIMM
8:	A system with a Pentium 4 processor runs only if the L2 cache is disabled in the system BIOS. Which of the following components must be replaced to solve this problem? (Choose one) COAST module SDRAM module(s) Processor SRAM TAGRAM chip
9:	You are upgrading a system with an Athlon XP processor with an FSB (Front-Side Bus) speed of 400MHz. Which of the following memory modules matches the speed of the processor's FSB? (Choose one) SDRAM PC2700 Rambus PC800 SIMM 60ns SDRAM PC3200
10:	You are adding 72-bit memory to a system which has 64-bit memory installed. Which of the following should be done to enable these modules to work in the same system? (Choose one) Enable ECC. Enable parity checking. Disable L2 cache. No changes needed.

Lab Exercises

Required equipment: motherboard or system reference manual with RAM configuration pages, working system with Internet access, ESD protection (wrist strap, antistatic mat), tools to open system, additional memory module(s) to add to system

Memory Detective

Objective : Determine the size and type of onboard memory and the upgrade options you have.

1. Start the system and use the methods covered in Chapter 2, "PC Anatomy 101," to determine

   • Memory size/speed in each socket

   • Empty memory socket(s)

2. Read the system documentation to determine

   • The highest amount of RAM you can install

   • The highest amount of RAM you can add without removing existing memory

   • Which combinations of memory modules are possible with the current memory installed

3. Visit a site such as Crucial.com (www.crucial.com) or Kingston (www. kingston .com) and try to look up your system or motherboard. Is your system or motherboard listed? If so, try to determine whether the memory listed for your system can be used in other systems.

4. Use the memory information you found in step 1 or your system/motherboard documentation to determine the standard designation for the memory in your system. What CL value (if any) is listed? Does the system use ECC or parity-checked memory?

5. If you have a suitable memory module, note the size of memory before you install it. Then install it (taking suitable ESD precautions ) and note the size of memory afterward.

   • Before size (MB)

   • Module size (MB)

   • After size (MB)

Does the after size of memory equal the before size plus the size of the module? If not, there might be a problem with the module, or it might not be compatible with your system.

Cache Detective

Objective : Determine the size and location of L1 and L2 cache on the system.

1. Start the system and use the methods covered in Chapter 2 to determine

   • Processor speed/model

   • Processor socket

   • L1 cache size

   • L2 cache size

   • L2 cache location

2. Look up the processor type in Chapter 4 and research the vendor Web site to determine whether a processor with more L2 cache is available. What speed and model of processor can be used to provide more L2 cache?

3. Review the motherboard/system manual and vendor resources online to determine if a processor with more L2 cache can be used in your system. What other changes are necessary (BIOS upgrade, clock speed, voltage, and so on)?

Answers to Practice Test

A1:	Answer C (install a second DIMM identical to the original DIMM) is correct. Dual-channel memory treats identical memory modules as a unit.
A2:	Answers B (ECC and parity checking require additional memory bits over those needed for data) and D (ECC can correct memory errors, whereas parity checking halts the system if a parity error occurs) are correct. Plainly, ECC is better than parity checking.
A3:	Answer C (the module could be either a DIMM or a SIMM) is correct. SIMM and DIMM refer to the contacts on the module, not the chips on the module.
A4:	Answer A (8MB, 70ns module with parity checking) is correct. Multiply 2MB by 4 to get the size (8MB).
A5:	Answer A (the module is a 256MB module) is correct. Multiply the first number by 8 to get the actual size of the module.
A6:	Answer B (PC2700) is the correct answer. 333MHz DDR modules have a throughput of 2,700MB/second, which is the same as 2.7GB/second.
A7:	Answer D (168-pin DIMM) is correct. The different sizes of connectors provide keying to prevent incorrect installation of memory.
A8:	Answer C (processor) is correct. The Pentium 4, like all processors since the Pentium II, integrates both L1 and L2 cache. If either cache fails, the processor is defective.
A9:	Answer D (SDRAM PC3200) is correct. Generally, you should match the FSB of the processor to the closest available memory for best performance.
A10:	Answer D (no changes needed) is correct. Systems without parity or ECC support ignore the additional bits.