Stretch tasks Secondary Storage

Round 1: Quiz Blitz

1. To keep data when the power is off Secondary storage is non-volatile, so files and programs survive being switched off.
2. SSD; USB flash drive Solid state means flash memory with no moving parts: SSDs, USB sticks and memory cards.
3. As pits and lands read by a laser CDs, DVDs and Blu-ray discs reflect a laser differently from pits and lands.
4. True That is why it is fast, silent and survives being dropped.
5. SSD, because it has no moving parts Durability matters most when a laptop is knocked about, and an SSD has nothing to break.
6. durability Durability is about physical damage. Reliability is about how likely it is to fail over time.
7. CD → DVD → Blu-ray → Hard disk drive About 700 MB, 4.7 GB, 25 GB, then a terabyte or more.
8. It is very cheap per terabyte for archive backups Tape is slow, with serial access, but nothing beats it for storing huge archives cheaply.
9. False Flash supports a large but finite number of write cycles.
10. Hard disk drive Magnetic hard drives give the most capacity for the money.
11. Capacity; Durability; Portability The six are capacity, speed, portability, durability, reliability and cost. Clock speed and cores belong to the CPU.
12. Access is serial: it winds through everything before it Serial access means reading in order, so data at the end takes longest to reach.

Round 2: Quick Fire

1. • It is non-volatile, so data is kept when the power is off
   • It gives far more capacity for the money than RAM
   • Data can be carried between computers or kept as a backup
   Model answer

   It is non-volatile, so files and programs are kept permanently when the power is off. It also gives far more capacity for the money than RAM.

2. • An SSD has no moving parts
   • A hard drive's spinning platters and head can be damaged if it is knocked or dropped
   Model answer

   An SSD has no moving parts. A hard disk drive has spinning platters and a moving read/write head, which can be damaged if it is knocked or dropped.

3. • Spinning platters coated in magnetic material
   • A read/write head on an arm magnetises tiny regions to stand for 1s and 0s
   Model answer

   It has spinning platters coated in magnetic material. A read/write head on an arm moves across the surface, magnetising tiny regions one way or the other to represent 1s and 0s.

4. • Low capacity
   • Slow to read and write
   • Easily scratched
   • It needs a disc drive, which many computers no longer have
   Model answer

   Optical discs have a low capacity compared with other storage, and they are easily scratched.

Round 3: Big Think

1. • An SSD
   • It has no moving parts, so it is durable if the laptop is knocked
   • It is fast, so large image files are saved quickly
   • It uses little power, helping the battery
   • The trade off is a higher cost per gigabyte
   • Its capacity is now big enough, such as 2 TB
   Model answer

   I recommend an SSD. It has no moving parts, so it is far more durable when the laptop is knocked or dropped outdoors. It is also much faster, so large image files are saved quickly, and it uses less power, which helps the battery last. An SSD costs more per gigabyte than a hard disk, but a 2 TB SSD gives enough capacity, so the extra cost is worth it.

2. • Magnetic gives high capacity at low cost
   • Magnetic has moving parts, so is slower and can be damaged
   • Solid state is the fastest
   • Solid state costs more per gigabyte
   • Solid state has a finite number of write cycles
   • Optical discs are cheap and portable, good for distributing software
   • Optical has a low capacity and scratches easily
   • Optical discs are read by a laser from pits and lands
   Model answer

   Magnetic storage, such as a hard disk drive, gives high capacity at a low cost per gigabyte, but it has moving parts, so it is slower and can be damaged if dropped. Solid state storage is the fastest and has no moving parts, so it is durable and silent, but it is more expensive per gigabyte and has a finite number of write cycles. Optical discs are read by a laser from pits and lands. They are cheap and portable, which suits distributing software, but they have a low capacity, are slow and are easily scratched.

This or That

1. A DVD Optical discs are read by a laser bouncing off pits and lands. An SSD uses flash memory.
2. A hard disk drive A hard drive has spinning platters and a moving head. Flash memory has no moving parts.
3. Optical discs Discs cost very little each, and a read-only disc cannot be altered.
4. An SSD With no head to move, flash memory reaches data far quicker.
5. A limited number of write cycles Flash is non-volatile, but each cell can only be written so many times.
6. Magnetic tape Tape costs very little per terabyte, which is why it is still used for big archive backups.
7. The characteristic that makes it suitable Name the characteristic and why it matters: no moving parts, so more durable when carried.
8. A single-layer DVD A CD holds about 700 MB. A single-layer DVD holds 4.7 GB, and a Blu-ray 25 GB.

Memory Match

• A 5 HDD: Magnetic platters read by a moving head
• B 3 SSD: Flash memory with no moving parts
• C 2 Blu-ray: An optical disc holding about 25 GB
• D 6 Durability: Surviving knocks, drops and moisture
• E 1 Portability: How easily a device is carried
• F 4 Capacity: How much data a device can hold

Sort It

1. Solid state The fastest to read and write With no moving parts, an SSD reaches data quickest.
2. Optical Data is stored as pits and lands Pits and lands on a disc are read by a laser.
3. Solid state Flash memory with no moving parts That is the definition of solid state storage.
4. Magnetic Can be damaged if knocked while working A knock can make the moving head hit the spinning platter.
5. Optical Easily scratched A scratch on a disc can stop the laser reading the data under it.
6. Magnetic Spinning platters and a moving read/write head A hard disk drive is magnetic: the head magnetises regions of the platters.
7. Optical Read by a laser CDs, DVDs and Blu-ray discs are all read by a laser.
8. Solid state Has a finite number of write cycles Each flash cell can only be written a limited number of times.
9. Optical A CD holds about 700 MB CDs are optical discs, with a small capacity by modern standards.
10. Magnetic The lowest cost per gigabyte for a computer's main drive A magnetic hard drive gives the most capacity for the money.
11. Magnetic Used on tape for cheap archive backups Magnetic tape is the cheapest storage per terabyte, with slow serial access.
12. Solid state Used in USB sticks and memory cards USB sticks and memory cards use the same flash memory as an SSD.