Storage

Any storage directly accessed by the CPU RAM, ROM and Registers/Cache

It’s much faster to access data from PS than SS

• Volatile - All data lost when computer turns off • The computer’s working memory • Can be written to, and read from

• Non-volatile - data permanently on disk • Used for computer’s start-up instructions (Bootstrap) • Read-only - can’t be changed

Needed for longer term storage of data because it is non-volatile. External devices are also portable and can have large capacities

Require little power and generate little heat Lack of moving parts, therefore small, reliable and portable Much faster than hard disks, and don’t require cooling equipment

Cheaper than SSDs

Short/medium term storage of music/video Can last 10-25 years

• Microscopic transistors act as control gates and floating gates to control the flow of the current • Current flowing = 1 • No current = 0 • Use NAND or NOR gates

• A laser reflects light off the surface of a disk with a spiral track of lands and pits • When the laser hits the the curved start/end of a pit, the light is refracted and a 1 is recorded • When light is reflected either from the land or pit, a 0 is recorded

• Hard disks are magnetic surfaces divided into tracks and sectors • They rotate around a spindle and a read/write head is moved onto the correct track • Particles on the magnetic disk are polarised (north = 0, south = 1) • The read/write head must be parked once operation is finished, otherwise it will break

When there isn’t enough space in RAM for all of the programs and data that are being used

• Small section of hard drive reserved to act like RAM • When program in VM is needed, it is swapped with something in RAM • This could cause your computer to slow down as it is a further distance to get to hard drive than to RAM

Remote file storage on someone else’s servers. Often done with major third-party companies.

Physical devices are still needed to store data in cloud storage

• No need to purchase local storage devices • Files are automatically backed up without user input • Remote access to your files from any Internet connected device, anywhere in the world • Enables easier file-sharing/collaboration • More environmentally friendly (One cloud storage server > millions of individual servers

• May need to commit to annual subscription • Backup/restoring could be slower than local storage • Security of the data will be managed by a third party (outside of user’s control) • Need an Internet connection to access data

• Network security has improved, so users more comfortable with risks assosicated with cloud storage • Large capacity data storage costs have improved • 4G and 5G networks have enbaled much faster browsing/download speeds to access data