1.1.3 // Input, Output & Storage Flashcards
1.
What do RAM and ROM stand for?
- Random Access Memory
- Read-Only Memory
Describe the properties of ROM and what it may contain.
- Non-Volatile (Will not lose memory when powered off)
Usually contains: - BIOS: Basic Input Output System
- Startup instructions that boot up the computer
- Checks hardware is working through the POST (Power On Self Test)
BIOS, Bootstrapper and POST!
Describe the properties of RAM and what it may contain.
- Volatile (Will lose stored memory on poweroff).
- Can be read from and written to quickly.
Usually contains:
* OS (Operating System) that gets loaded into RAM from the HDD.
* Running programs / Software in use
* Data currently in use by the software.
OS, Programs, and Data in Use!
Remember, there are primary and secondary storage types.
Talk about the HDD, and how it may read/write data.
- Secondary storage type
- Magnetic storage
- It has magnetic platters that spin while data is read/written by drive heads; drive heads only do so if under the right sector (part of the concentric platter).
What is Disk Latency?
The delay between a data r/wr request and the storage device’s response.
What is Seek Delay?
This is a type of Disk Latency.
The time the drive head takes to move across the disk to the appropriate track.
What is Rotational Delay?
This is a type of Disk Latency.
The time the disk takes to move the correct sector underneath the r/wr head.
What is Transfer Time?
This is a type of Disk Latency.
The time taken for the data transfer out of the storage device.
What is Cloud Storage?
Offshore data storage on servers usually using magnetic or SSD methods of storage, ran by subscription-based businesses.
What are some benefits of using Cloud Storage over physical storage?
- Accessibility: Data can be accessed on any device with internet connection.
- Scalability: Data capacity can easily be changed with customer needs.
- Security: Data is frequently backed up, ensuring data security in times of breaches or system failure.
What are some drawbacks of using Cloud Storage over physical storage?
- Dependence on Internet: Accessing data needs a stable internet connection.
- Security Concerns: Breaches or unauthorised accesses may happen, compromising sensitive user data.
- Ongoing Cost: Unlike physical storage, subscription costs may accumulate over time.
Describe the structure of the SSD.
A Solid State Drive contains millions of NAND Flash Memory Cells (organised in pages & blocks) managed by a controller that handles data access.
Describe how the SSD may read/write data.
- When reading, the SSD retrieves data directly from memory cells (no mechanical movement!)
- When writing, contents of a block are first erased (even if writing to one page); slowing down write speeds
What are some benefits of using an SSD over HDDs?
- Speed: r/wr speeds are much faster than traditional HDDs; they have quicker boot times, file transfers and application loading speeds.
- Durability: Reduced impact on data and transfer speeds when physically hit, as an SSD has no moving parts.
- Energy Efficiency: They consume less power than HDDs, extending battery life and reducing energy costs over time.
What are some drawbacks of using an SSD over HDDs?
(I only wrote 2)
- Cost per GB: SSDs are more expensive than HDDs per GB, making high-capacity SSDs less affordable for users on a budget.
- Limited Write Cycles: SSDs have a limited number of wr/erase cycles, causing degradation over time. This is less of an issue for casual users.
What is Virtual Memory, and why is it used?
Also, why can frequent use be bad?
- A memory management technique of an OS that uses HDD space as temporary ‘RAM’, enabling it to run more applications than the real RAM could handle.
- Because data access is significantly slower, frequent use of VM can cause performance degradation, known as ‘Thrashing.’
How do Magnetic Storage devices store Binary data?
Think about pulses!
- Magnetic storage devices store data by aligning magnetic domains (tiny magnetized regions) to represent 0s and 1s.
- The read head detects changes in magnetic field direction for 1s, and no change for 0s.
Why are the Capacities of CDs, DVDs and BluRay different despite being the same physical size?
Note that they are all ‘Optical’ Storage devices.
Because as different wavelengths burn smaller pits, the spiral track on a disc can be more tightly wound; increasing capacity.
How do Optical Storage devices store Binary data?
- A high-powered laser burns pits onto a disc.
- A low-powered laser then detects the reflection from pits and lands. Only a pit start or end deflects the laser in a way for the sensor to read it as a 1.
What are the uses of each of the 3 storage types?
- HDDs: Bulk Data Storage and Long-Term Archiving; Videos, Photos or Backups.
- SSDs: Installing OSs and Software; also used in high-performance Gaming and Computing.
- Optical: Distributing Music, Films, etc; also used in Long-Term data archival.
What are the usual capacities of each of the 3 storage types?
- HDDs: 500GB-20TB @ 80-160MB/s, depending on the RPM of the drive (5400-7200). 10-15ms to access.
- SSDs: 120GB-8TB @ 200-550MB/s for SATA SSDs; NVMes can reach 1000-7000+MB/s. 0.1ms to access.
- Optical: CDs: 700MB @ 1.2-7MB/s. DVDs: 5GB @ 11MB/s. BluRay: 25GB @ 36-72MB/s. 100ms+ to access.
What is an Output Device?
A device that takes data in a digital form and converts it into another format that humans can process, such as light or sound or vibrations.
What is an Input Device?
A device that lets you pass information into a Computer System
