Memory

1. Memory

2. DRAM • Dynamic random access memory • Main form of memory in personal computers and game consuls • Stores each bit of data in a separate capacitor within an integrated circuit

3. DRAM • Capacitor can be either charged or discharged • Called dynamic memory because if capacitors must be periodically charged • If not charged the information stored in the capacitors will eventually be lost

4. DRAM • Type of memory used by the CPU • Each chip holds rows and columns of data • A DRAM chip that holds 1,048,576 rows and 8 columns would be 1 M x 8 chip • “M” means megabyte • Originally RAM came in one bit wide sticks • Now RAM is available in 32-bit and 64-bit sticks

5. DRAM Advantages • Structural simplicity • Only one transistor and one capacitor per bit • SRAM has sic transistors • Inexpensive to manufacture • Small in size • Can hold larger amounts of information

6. DRAM Disadvantages • Loses data when power is removed • Because data needs to be refreshed it is slower than SRAM

7. SRAM • Static random access memory • Memory is lost once the power is lost • Typically find that SRAM is used in: • cache memory, • hard drive buffers and in • other electronics such as children's toys • Electronic games

8. SRAM Advantage • Does not loses data when powered down • Date does not need to be continuously refreshed • Faster then DRAM

9. SRAM Disadvantage • Expensive to manufacture • Larger than DRAM

10. SDRAM • Synchronous dynamic random access memory • Because it is synchronous it is tied to the system clock • Allows for higher transfer rates with interfaces possible • Has to wait for a clock signal before it can respond to control inputs and synchronize with the computer

11. SDRAM • Introduced in 1996 on a dual inline memory module stick (DIMM) • Had varying number of pins • DIMM slots that stored the memory referred to as “banks”

12. SDRAM Advantages • Allows computers to run at higher mega hertz • Extremely protective of data bits that are stored into the computer • This means it will not allow any corrupt material to be stored in it's drives.  • Uses pipelining • that allows more then one command to be accept at one time

13. SDRAM Disadvantages • Not good at checking to ensure that electrons in the computer system are working properly • This means it needs to be constantly refreshed to ensure that no information is not lost

14. RAMBUS • Leader in the computer memory industry • Develops and licenses high-performance memory logic and circuit design technology and provides licensees with product design • Created RDRAM

15. RDRAM • Developed for the Pentium 4 by Rambus • Can handle speeds up to 800 MHz • Not well accepted by the industry because of high cost and production delays

16. RDRAM • Came in two sizes • 184-pin (desktops) • 160-pin (laptops) • Had speed ratings of 600 MHz, 700 MHz,800 MHz, or 1066 MHz • Had to be installed in pairs because it alternated between two stick to increase speed

17. RDRAM • All slots on motherboard had to be populated • Roadblocks faced by RDRAM • Technology was owned entirely by Rambus • Expensive • Rambus and Intel made a closed deal and RDRAM only worked on Pentium 4 systems using Intel

18. DDR SDRAM • Double data rate • Same principle as RDRAM • Doubled speed by making two processes for every clock cycle • Cost only slightly more than regular SDRAM • 184-pin for desktops • 172-pin or 200 pin for laptops

19. DDR SDRAM • Sticks are notched so that the wrong stick can not accidentally be placed in the wrong slot • Eventually became adopted as the standard system RAM • In 2003 Intel ceased producing for RDRAM and adopted SDRAM • Fastest version ran at 4.8 gigabytes per second

20. DDR2 • Successor to DDR • Runs faster than DDR by clock-doubling the input/output circuits • Uses less power • Uses 240-pin DIMM which is not compatible with DDR

21. DDR3 • Newest in line of DDR • More efficient architecture • 30 percent lower power consumption • Uses a 240-pin DIMM, which is slotted differentially which prevents users from installing the wrong ram • Double the buffer of DDR2 from 4 to 8 bits

22. DDR3 • Extending memory profile (xmp) • Enables RAM to be overclocked • Triple-channel memory • Works like dual channel but uses three sticks instead of two

23. DDR / DDR2 / DDR3 • Double data rate • Neither forwards or backwards compatible • Double data rate means that DDR can achieve nearly twice the bandwidth of a single data rate (SDR) SDRAM running at the same clock frequency, due to this double pumping. DDR1

24. DDR2 Versus DDR3 • http://www.youtube.com/watch?v=mZAQ4Y0tjts&feature=related

25. Single Sided and Double Sided • Single sided have chips on only one side of the sick • Double sided have chips on both sides of the stick • Majority of sticks are single sided • Some motherboards are not compatible with double sided ram

26. Latency • The delays incurred when a computer tries to access data from the stick of RAM • The latency number reflects how many clicks of the system clock it takes before the RAM responds • Sticks with lower latency are “faster” because they have smaller delays • One stick with lower latency may cost far more than a the same stick with a higher latency

27. Parity vs. Non-parity • Parity RAM was the first form of error detecting RAM • Uses for computers that must be precise all the time • On occasion there will be an error, parity RAM detects the error

28. ECC vs. non-ECC • Error correction code • Detects any time a single bit is incorrect • It fixes any errors on the fly • ECC RAM is slower than non-ECC RAM because of the error checking • Non- ECC RAM does not do error checking

29. Single channel vs. dual channel • Dual channel is faster and allows for more DIMMs • Dual channel means that you have two channels/pathways for your CPU to access your RAM r • Single channel means there is only one channel • More channels allows for more data to be transferred which results in more speed

30. Installing RAM • http://www.youtube.com/watch?v=pemQxhE7Jhk

31. Install and configure peripherals and input devices • The following should automatically configure, or only need their attached installed CD to configure • Keyboard • Bar code reader • Multimedia • Mouse • If will not configure you may need to download a driver

32. Biometric Authentication • Uses some sort of physical characteristic to identify the user, such as • Face • Eye • Fingerprint • Handprint • Free face recognition software: • http://www.youtube.com/watch?v=hUc_2OR7zQ8

33. Touch screen • A touch screen allows the user to physically touch the screen to open, close and move through an application • http://www.youtube.com/watch?v=6jhoWsHwU7w&feature=related

34. KVM Switch • The KVM Switch allows the user to access different computers using a single monitor, keyboard, and mouse. • KVM stands for Keyboard, Video, and Mouse • When installing turn off all computers that will be connected. • Connect all computers to the switch then turn back on the computers. • Windows should recognize the new devices and automatically install them.

35. Helpful Links • http://www.youtube.com/watch?v=E4PIDZrBGzQ • http://www.youtube.com/watch?v=rT-wxXHswbE