V 2012.13. 2 Avon High School Tech Crew Agenda Old Business New Business Week 2 Meeting Review Week...
Transcript of V 2012.13. 2 Avon High School Tech Crew Agenda Old Business New Business Week 2 Meeting Review Week...
V2012.13
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Agenda
• Old Business• New Business• Week ‘2’ Meeting Review• Week 3 Topics:
– Intro to Memory– Continue to trouble shoot our PC
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Old Business
• Sub-groups– Graphics– Web Design– App Development– Other?
• Scorer’s table job• Email me with interest!• Fundraising• Remember … participate!
– Read email, polls, requests, etc.
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New Business
• District Tech Department Help– Install Office 2010– Repair Computers
• Contact Info– Request your name/year
• Comments on Twitter• T-Shirts
– Limited sizes/colors
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Week 2 Meeting Review
• Intro to Computer Repair– What did you think?– Any follow-up questions?
• Our non-working PC …– Did you answer the poll question?
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Intro to Memory
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Intro to Memory
• Common Terms• Common Types• How it works• Resources
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First, Some Common Terms
Term Definition Purpose
Volatile Computer memory that requires power to maintain the stored information
RAM
Non-Volatile Computer memory that can retain the stored information even when not powered
ROM
DIMM Dual in-line memory module Difference between SIMMs and DIMMs is that DIMMs have separate electrical contacts on each side of the module
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Common Types of Memory
Type Definition Purpose
BIOS Basic Input/Output System Boots firmware, POST
ROM Read-only memory Used to store firmware
Cache Smaller, faster memory Reduce average time to access main memory (L1, L2, L3)
RAM Random-access memory Data accessed quickly in random order, in same amount of time
DRAM Dynamic random-access memory Data fades unless the capacitor charge is refreshed, very high densities
SRAM Static random-access memory Holds charge, typically faster, less dense, more expensive
SDRAM/DDR Synchronous dynamic random-access memory
Synchronized with the computer's system bus (DDR1, DDR2, DDR3)
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DDR (SDRAM) Memory
• Double Data Rate• Two data transfers
per cycle• Higher bandwidth
– DDR3 has the ability to transfer data at twice the rate of DDR2
• Uses less power (30%)
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Common Types of Memory
Type Definition Purpose
Flash Non-volatile computer storage chip that can be erased and reprogrammed
Used in USB drives, memory cards, solid-state drives
SGRAM/GDDR Synchronous graphics random-access memory, Graphics Double Data Rate
Specialized form of SDRAM for graphics adaptors (GDDR3, GDDR4, GDDR5)
Solid State/SSD Solid-state drive, no moving mechanical components, retains data without power
Data storage device
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DDR vs GDDR
• GDDR is built for much higher bandwidth, thanks to a wider memory bus
• GDDR has lower power and heat dispersal requirements compared to DDR, allowing for higher performance modules, with simpler cooling systems
• DDR1, DDR2, and DDR3 have a 64 bit bus (or 128 bit in dual channel). GDDR3, comparatively, commonly uses between a 256 bit bus and 512 bit bus, or interface (across 4-8 channels)
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DRAM vs SSDs
• DRAM is used to run stuff• SSDs are where you store stuff
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Memory Hierarchy
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Memory Hierarchy
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Why so many types of memory?
• Different pieces of a computer system have different requirements for speed, size and cost
• Computer designers have solved the cost problem by "tiering" memory
• Using expensive memory in small quantities and then backing it up with larger quantities of less expensive memory
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So, how does memory work?
• The basics …• Each memory ‘cell’ is comprised of:
– Transistor– Capacitor
• Each cell can hold 1 bit of information• Cell contains a data input line, a data output line,
a Read/Write line and a select line – The select line activates the cell and Read/Write line
tells it either to output its contents or store what is at its input
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So, how does memory work?
• Cells are organized in a grid pattern, rows columns
• Data (‘line’) inputs and outputs for each cell are connected together to form an ‘array’
• Data is written to a specific row and column of the array, defined as the ‘binary address’
• CPU can access the data from that specific address
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So, how does memory work?
• Data lines from multiple memory chips are grouped to form a ‘data bus’
• Data bus has the following characteristics:– Bus width refers to the number of bits that can be
sent to the CPU simultaneously– Bus speed refers to the number of times a group of
bits can be sent each second– Bus cycle occurs every time data travels from
memory to the CPU
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So, how does memory work?
• Memory Controller– Manages the flow of data going to and from the main
memory– Contain logic necessary to read and write to DRAM,
and to "refresh" the DRAM– It can be a separate chip or integrated into another
chip (like the CPU)– Part of the ‘Northbridge’
• Located closest to the CPU (or on the CPU) and controls the fastest components on the motherboard: the CPU, video card slot and RAM
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When/Why would you install memory?
• To improve performance– O/S, apps getting larger
• To prevent disk ‘swapping’– Windows creates ‘virtual RAM’ – In the form of ‘pagefile.sys’ on your hard drive
• But there are other factors that impact performance …
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Summary
• Different types of memory address different needs
• Used in almost every phase of a computer system
• At a high level, memory is comprised of cells, arrays, data bus
• Operated by a memory controller which communicates with the CPU
• Generally helps improve performance
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Troubleshooting
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Our Non-Working PC …
• Dell 2400• No output to screen• Blinking amber light (power)• Fans are not spinning
• What would you do next?• Ideas …?