3.2 Given a scenario, Install the appropriate RAM Flashcards
What happens when a process is executed?
Image is loaded from the fixed disk into system memory
Instructions are fetched from system memory & into the CPU’s cache & registers as required. This process is handled by the memory controller
How is system memory implemented as?
RAM
Meaning of RAM?
Random Access Memory
What is RAM faster than?
Hard drives
What does it mean that RAM is volatile?
It can only store data when it is powered on
What is system memory (RAM) measured in?
Gigabytes (GB)
What does the amoung of system RAM determine?
PC’s multitasking capability & efficiency in handling large files
What does pagefile or swap space refer to?
Portion of a hard drive reserved for virtual memory
What does virtual RAM refer to?
Concept of using storage to supplement physical RAM
With virtual RAM, what does the OS do?
Assigns memory locations to processes in 4KB chunks called pages
Why does the OS use a page-based systen in Virtual RAM?
For memory controller to move inactive pages to swap space to free up physical RAM
It retrieves pages from the swap space to physical RAM when required by process execution
Why does paging activity in Virtual RAM slow down the computer?
Disk transfer rates are slower than RAM transfer rates
Another purpose of virtual RAM besides supplementing physical RAM with storage?
To protect the operation & integrity of a PC
How can virtual RAM protect the operation & integrity of a PC?
Allowing the OS to oversee a shared virtual memory for multiple processes
Virtual memory abstraction enhances system security and stability by centrally managing memory allocation, preventing process interference, and enforcing security measures, surpassing the reliability of direct access to physical RAM for each process.
What does the bus between the CPU, memory controller, & memory device consist of?
Data pathway & address pathway
What does the data pathway width determine?
The bus between the CPU, memory controller, & memory devices consists of a data pathway & address pathway
How much data can be transferred per clock cycle
How wide is the data path/bus in a single-channel memory controller?
The bus between the CPU, memory controller, & memory devices consists of a data pathway & address pathway
Typically 64 bits wide
This means 64 bits of data can be transferred between the memory controller & memory device in a single operation
What does the address bus width determine?
The bus between the CPU, memory controller, & memory devices consists of a data pathway & address pathway
CPU’s memory tracking, limiting the system’s physical & virtual memory capacity
This means the amount of memory locations the CPU can keep track of
How much address space can a 32-bit CPU with a 32-bit address bus access?
Up 4GB of address space
This means that 32-bit CPUs only support up to 4GB of RAM
How much address space can a 64-bit CPU with a 48-bit address path/bus access?
Up to 256TB of address space
In theory, a 64-bit CPU could implement a 64-bit address space (16 exabytes), but most 64-bit CPUs actually use a 48-bit address bus
What type of memory is mainly used in modern computer systems?
DDR SDRAM (aka RAM)
Meaning of DDR SDRAM?
Double Data Rate Synchronouse Dynamic Random Access Memory
3 types of memory used in computer systems?
- DRAM
- SDRAM
- DDR SDRAM
How does Dyanmic RAM (DRAM) store data?
As electrical charges in bit cells, each compromising a capacitor
A transistor reads whether the capacitor hold a charge, representing 1, or not, representing 0
Why is Synchronous DRAM (SDRAM) so-called that way?
Its speed is synchronized to the motherboard system clock
How does DDR SDRAM add on to SDRAM?
Makes 2 data transfers per clock cycle
This effectively double the data transfer rate compares to traditional SDRAM
How are DDR memory modules labeled?
Using the max theoretical bandwidth
i.e. PC1600, PC2100, etc.
In this memory example - DDR-200 PC-1600 - What does DDR-200 mean?
Data rate of 200 MT/s
MT/s = Megatransfers per second
The DDR-200 designation signifies a 100MHz internal memory clock speed. With DDR, the effective data rate doubles the clock speed, resulting in 200 MT/s
What is a memory module?
PCB that groups RAM devices to act as a single unit
Memory modules are produced in different capacities. Each DDR generation sets an upport limit on the max possible capacity
What memory module do desktops use?
DIMM
The notches on the edge connector identify the DDR generation and ensure proper insertion. DDR DIMMs often have heat sinks due to high clock speeds
Meaning of DIMM?
Dual-Inline Memory Module
What are memory modules vulnerable to?
ESD
Always take anti-ESD precautions when handling & storing these devices
What speeds should memory modules match for optimal performance?
Motherboard’s bus speed
What occurs if memory modules with different speeds are installed on the MOBO?
MOBO = Motherboard
System runs at the speed of the slowest component
What memory modules do laptops use?
SODIMM
Meaning of SODIMM?
Small Outline DIMM
What does dual-channel memory mean?
There’s 2 64-bit pathways through the bus to the CPU
This means that 128 bits of data can be sent per transfer rather than 64 bits.
For dual-channel configuration, consult system documentation to find correct slots. Motherboards usually have 4 DIMM slots in color-coded pairs, each pair representing a channel
What may you need to do to use Multi-channel memory?
Enable it via PC’s firmware settings
Why do ECC RAM modules have an additional processor chip?
To handle data error correction tasks
