CompTIA A+ 220-901 (notes from ITPro.TV) (In Progress)

Category 7 (CAT 7)

10, 100, 1000BaseT, 10 Gigabit Ethernet, speeds up to 10 Gbps, used in data centers and other bandwidth intense environments. Uses a GG45 (tera) connector, not RJ45.

Category 7a (CAT 7a)

10, 100, 1000BaseT, 10 Gigabit Ethernet, speeds up to 10 Gbps, used in data centers and other bandwidth intense environments. Uses a GG45 (tera) connector, not RJ45.

Category 6e (CAT 6e)

10, 100, 1000BaseT, 10 Gigabit Ethernet, with speeds up to 10 Gbps, uses an RJ45 connector.

DVI-A

16 pin DVI connection - 1920 x 1200 at 3.96 Gbit/s - Analog only

DVI-D (Single Link)

18 pin DVI connection - 1920 x 1200 at 3.96 Gbit/s - Digital only

DVI-I (Single Link)

22 pin DVI connection - 1920 x 1200 at 3.96 Gbit/s - Integrated, combines digital and analog in the same connector.

DVI-D (Dual Link)

24 pin DVI connection - 2560 x 1600 at 7.92 Gbit/s - Digital only

DVI-I (Dual Link)

24 pin DVI connection - 2560 x 1600 at 7.92 Gbit/s - Integrated, combines digital and analog in the same connector.

Mini-DVI

32 pin compact DVI connector - 1920 x 1200 at 3.96 Gbit/s - used mostly on older Apple laptops.

Serial ATA (SATA)

7 Pin internal component connector with different versions including an external variant. Used to connect storage (Mechanical drives, SSD's and optical drives) to the motherboard. All internal SATA connections have a small notch that prevent the cable from getting plugged in the wrong way. Some SATA cables have 90 degree angles to help with cable management and in tight spaces.

Thunderbolt

Developed by Apple and Intel, sends out video signal as well as PCI-E connectivity, which has super high speeds but varies based on version. Thunderbolt has a max range of 3 meters and can support up to 6 devices off of one connection as well as "daisy chaining" v1 was 10Gbps, v2 was 20Gbps and v3 is 40Gbps.

DVI

Digital video interface - digital* output with no sound and varying types each with different amounts of pins. 4.5 meter (15 feet) max length. *Can vary depending on the cable

DIMM

Dual Inline Memory Module - memory chips on both sides of the RAM module.

Firewire (IEEE 1394)

High speed external connection that comes in two variants Firewire 400 and Firewire 800. Popular with audio and video production. Was used by Apple in many of its products, however it has since fallen out of favor for faster connections. Some variants include power.

Micro SD

Introduced in 2005 and available in the same types of varying capacity standard (HC, XC, UHS) as the full size SD card and is used by many small devices such as smartphones and GoPro's. Can be placed inside an adapter to be used in a standard SD size reader.

Component Connectors

Looks very similar to RCA but has blue and green connectors to separate out video into different channels to provide a higher quality image which is typically better than VGA.

Serial ATA 1 (SATA 1 or SATA I)

Serial AT Attachment 1 - 7 pin internal connection that supports speeds of up to 1.5 Gbit/s

Serial ATA 2 (SATA 2 or SATA II)

Serial AT Attachment 2 - 7 pin internal connection that supports speeds of up to 3.0 Gbit/s

Hybrid Drives

Small SSD paired with conventional drive. The SSD portion is used to store the operating system and the conventional mechanical drive used to store everything else. This was implemented heavily in the days of Windows Vista to get the faster performance without the heavy cost of the newer SSD technology.

ATX

Standard tower case motherboard, made for building desktop systems that will be full blown computer platforms or even gaming systems. These max out at about 7 expansion slots. (Ex. 12" x 9.6")

Micro USB 3.0 B Connector

9 pin USB 3.0 connector, has two connections side by side, used in smaller devices like smartphones, and external hard drives.

USB 3.0 B Connector

9 pin USB 3.0 connector, has two stacked connectors.

Thermal Paste/Compound

A paste that is placed between the surface of a component, typically the CPU or GPU and the heatsink/cooler. This paste smooths out the surface and fills in any small imperfections to get the least amount of air between the two surfaces which can cause heat issues. The compound is made of thermally conductive material to help more effectively draw heat away from the surface of the CPU or component. The contents of the paste/compound can differ depending on brand but they all aim to accomplish the same goal. Only a small amount is needed, about the size of a grain of rice.

FM1

AMD based APU that includes AMD Fusion APU

AM3+

AMD based CPU that includes Bulldozer and AM3 Processors

AM3

AMD based CPU that includes Phenom II, Athlon II, Semprion and opteron processors.

FM2+

AMD based CPU that includes Steamroller based (Kaveri and Godavari) Rich land and Trinity

FM2

AMD based CPU that includes Trinity and Rich land APU, Athlon X2 and X4

APU

Accelerated processing unit announced by AMD in 2011. Combines the CPU and GPU onto one chip.

Blu-Ray

Another optical disc format, this type of disc is still widely used today in HD movie releases and PS4 game discs. This format beat out HD DVD and can store 25-50GB of data. There are Blu-ray burners out there that allow for the ability to write data to the discs but they aren't as prevalent as DVD and CD burners were/are.

BIOS

Basic input output system - the firmware for the motherboard and is installed/burned into the chip on the board at the factory, known as ROM. Tells the motherboard and system where to look for hardware.

BNC

Bayonet Neil-Concelmen connector, quick connect and disconnect locking connection. Typically found on coaxial cables, has two locking lugs that rotate to securely connect the cable to the device.

Triple Channel RAM

Can address 192 bits of data through the memory bus, will require 3 or 6 slots on the motherboard. If the mother board has 4 slots it will indicate which slot is not part of the triple channel setup by making it a different color. All memory modules are required to be identical for this to work properly.

Single Channel RAM

Can address only 64 bits of data at a time and if the data is on a different memory module the cpu will have to stop reading the current memory module to access the needed module.

CPU

Central Processing Unit - the brain of the computer, handles all instructions of a computer program by carrying out the math and I/O operations. In computers the CPU is the processor. In consumer systems they typically come from two main manufacturers Intel and AMD. Rated by clock speed, which is cycles per second (typically in Gigahertz, GHz) so a 3.2 GHz processor is running at about 3,000,000,000 cycles per second. CPU's come in two variants, 32-bit and 64-bit which refer to the amount of bits the address bus can handle, ultimately effects how much RAM the system can handle and recognize, 32-bit being limited to 4GB and 64-bit being able to handle more than 4GB but often limited by the software to around 128GB.

Quad Core Processor

Contains four processing cores and each is running at the specified clock speed, which will cut the time it takes to process data in half from the dual core, each being able to handle quarter of the workload simultaneously. Most quad cores will have hyperthreading which cuts each of the physical cores in half so to the computer there appears to be 8 logical cores and will help handle data processing a little bit more efficiently, the benefit of hyperthreading will vary depending on the CPU architecture.

Single Core Processor

Contains one processing core and all data in handled by the single core inside.

Dual Core Processor

Contains two processing cores and each is running at the specified clock speed, which will cut the time it takes to process data in half, each being able to handle half the workload simultaneously.

Coaxial

Copper wire with shielding and insulating material around it that is used for transmitting data and is typically seen in cable TV and external ISP connections into the modem. There are many ways these cables can terminate with threaded screw ends, push ends or BNC connectors. Also known as Coax and has a very long range. Not found running into the back of desktop systems typically but is common in video and audio production environments.

Dual Channel RAM

Creates blocks which simulate have one larger memory bus, pulling 128 bits simultaneously from two memory modules rather than just one. This will require the motherboard to have at least two RAM slots, and it should be noted that most will color coordinate the two slots that belong together. All memory modules are required to be identical for this to work properly.

DDR

Double Data Rate - allows for two bits to be transferred on each cycle, doubling the speed. There are various versions of DDR and each increase from DDR to DDR3 has been exponential.

DDR2

Double Data Rate 2 - allows for 4 bits to be transferred on each cycle.

DDR3

Double Data Rate 3 - allows for 8 bits to be transferred on each cycle.

Optical Drives

Drives that read media using a laser, includes CD, DVD and Blu-Ray discs (also HD DVD). There are optical drives that carry two lasers, one to read and one to write data, known as burners. There even was a type of technology that used a third laser to etch a label on the top of the disc known as Lightscribe.

Category 3 (CAT 3)

Ethernet 10Base T, speeds up to 10Mbps, uses a RJ45 connector

eSATA

External variant of the Serial ATA (SATA) standard that has the same speed as the version of SATA it is based off of with 7 pins. eSATA has more shielding to protect from electromagnetic interference and no notch. Sometimes eSATA ports will double as a USB A port using only 4 pins.

Category 5 (CAT 5)

Fast Ethernet 10BaseT-100BaseT, speeds up to 100Mbps used in Schools and Small Office or Home Office environments. Uses and RJ45 connector.

USB Type C

Fast, reversible USB 3.1 connector, capable of 10 Gbps and delivering much more power. (Similar look to Micro USB, image is wrong just the only one close enough for free version)

Firewire 400 (IEEE 1394a)

Firewire 400 comes in two connector types a 6 pin with 12 volts power and a 4 pin without power. Firewire 400 supports transfer speeds of 400 Mbps and has a max range of 4.5 meters (15 feet).

Firewire 800 (IEEE 1394b)

Firewire 800 has a 9 pin connector with 12 volts of power. Firewire 800 supports transfer speeds of 800 Mbps and has a max range of 4.5 meters (15 feet).

802.11b

First wireless standard (yes before 802.11a) and supports speeds of only 11Mbps at a range of 140 meters and operates on the 2.4GHz spectrum using FHSS.

Flash Drives (Thumb Drive, Flash Stick)

Flash storage that comes in many sizes, capacities, USB standards (1.1, 2.0, 3.0). The easiest and most common way to carry around data and be able to connect it to a system to access the contents. Can be used as bootable media to install OS's or clone drives. Flash drives are still stuck in the Gigabyte range.

Chipset

Found on the motherboard and handles all data going to and coming from the CPU. Most are broken down into Northbridge and Southbridge. Smaller boards will likely combine the North and south bridge into one chip.

FHSS

Frequency hopping spread spectrum , older wireless technology that was replaced by OFDM.

Category 6 (CAT 6)

Gigabit Ethernet, 10, 100, 1000BaseT, with speeds up to 1,000 Mbps, with RJ45 connector.

Category 5e (CAT 5e)

Gigabit Ethernet, 10,100,1000BaseT, with speeds up to 1,000Mbps, used by large businesses and College Campuses. Uses an RJ45 connector.

HDMI

High Definition Multimedia Interface - Digital signal capable of the same resolutions of DVI but at faster speeds, 18 Gbps or 2 GBps in 2.0, and carries audio as well as the video. HDMI plugs come in various form factors such as the standard A connector, then Mini and Micro HDMI all of which have 19 pin connectors and looks very similar. The HDMI B connector is larger and has 29 pins. Used in many devices and can be found in home theater setups as well. Range for HDMI can be up to 30-50 meters, but most aren't longer than 10 feet.

IR (IrDA) Wireless

Infrared wireless communication, short range line of sight wireless connection. Uses infrared lights to transmit data at a rate of up to 4Mbps from up to 1 meter away with LOS. Most commonly used in remotes or motion sensors, but can find some internet connected devices.

Socket 1156 (Socket H)

Intel CPU socket 8XX series i3, i5 and i7's

Socket 1366 (Socket B)

Intel CPU socket 9XX series i7's and some Xenon's.

Socket 1150 (Socket H3)

Intel CPU socket that includes Haswell and Broadwell processors.

Socket 2011 (Socket R)

Intel CPU socket that includes Sandy Bridge-E, Ivy Bridge-E, Haswell-E and Server Xenon E5.

Socket 1155 (Socket H2)

Intel CPU socket that includes Sandy bridge and Ivy Bridge processors.

Socket 775 (Socket T)

Intel CPU socket up to Core2, Core2 Duo and Core2 Duo EE (Extreme Edition).

Mini SD

Introduced in 2003 and is available in the same types of varying capacity standard (HC, XC, UHS) as the full size SD card and is the least popular form factor of the SD family. Also has an adapter to allow it to fit into standard SD card size readers.

Mechanical Hard Drive

Large capacity, cheaper storage solution that has a moving arm that reads data from the spinning platter (platters are made of glass or metal) inside the drive. Comes in two main sizes measured by the size of the internal platter, 3.5" drives (Desktop usage) and 2.5" drives (Laptop usage). Disks come in three speeds 5,400 RPM, 7,200 RPM and 10,000 RPM. The faster the drive spins the faster it reads data but the more heat and noise it makes which means it will likely die sooner. 5,400 RPM drives are cheaper, slower, cooler, quieter and uses less power which makes them ideal for laptops. Mechanical drives are about 500GB now on the low end and 1TB is becoming the new "standard" size.

RAID 1

Mirroring - Two drives, files are written to both drives, each having a full copy. With this type of array you only get the capacity of one of the drives since everything is written twice. There is no speed benefit to this array either but you can loose one drive and still have all data since both the drives have a complete copy of all files. Once a failed drive is replaced all of the files are then copied to the new drive. This can also be done with two RAID controllers, called duplexing, which eliminates the possibility of data being inaccessible due to a single RAID controller failing. Duplexing is more expensive but provides great data security.

MMC

Multimediacard is a type of flash storage that was used in digital cameras, primarily by Sony and have 7 pin connector, not common to find/use.

NFC

Near Field Communication - very short distance, max range of 4 inches, wireless communication standard that has seen adoption in smartphones for mobile payments and transferring small files between devices by touching them together. The speed NFC transfers data at is between 106 and 424 Kbps.

NUC

Next Unit of Computing - Small form factor computer that typically is sold as a barebones kit, only including the case, CPU, and mother board leaving the storage and RAM up to the user. These smaller devices are quiet and fairly new. They are very adaptable and can be used for home theater PC's, smaller servers and other various uses. Most are only a 7 inches in any directions and in a square/rectangular form factor.

PS2 Connector

Older style connector with 6 pin connector and used for Mice and Keyboards. Normally the mouse and keyboard connectors are color coded, green for mouse and purple for keyboard, they may look the same inside but they won't fit into the wrong color. It is recommended that the device be off before plugging in these types of connectors. You can also get an adapter that will take both the mouse and keyboard PS2 connectors and allow you to plug it in over a single USB port.

CD-R

One time writeable compact disc that required a CD burner drive to etch the data onto the disc, could hold 700MB of data, required an optical CD drive to access data. The drive uses different laser for reading and writing data.

DVD-R

One time writeable digital versatile disc that required a DVD burner drive to etch the data onto the disc, could hold 4.7GB of data, required an optical DVD drive to access data. Later variants called Double Layer DVD's allowed for more storage space on the disc, 8.5GB. The drive uses different laser for reading and writing data.

DisplayPort

Open standard that is very similar to HDMI with a 20 pin connector and supports full digital signal with audio, but can carry USB and other data types. Max range is about 3 meters. Comes in a Mini Displayport which is popular for laptops and can be used to send video out from a Thunderbolt port.

Blu-ray drive

Optical disc reader that can read data stored on a blu-ray disc, digital versatile disc and compact disc. The only other moving part in a computer besides mechanical hard drives and fans.

CD Drive

Optical disc reader that can read data stored on a compact disc. The only other moving part in a computer besides mechanical hard drives and fans.

DVD Drive

Optical disc reader that can read data stored on a digital versatile disc as well as compact discs. The only other moving part in a computer besides mechanical hard drives and fans.

OFDM

Orthogonal frequency division multiplexing, newer technology used in wireless routers to help cut down on interference on the 2.4GHz spectrum.

Motherboard

PCB that all internal computer components plug into and provides power and communication to them. Motherboard contains the chipset, expansion slots, fan headers, I/O connectors and media connecting points. Most will have the RAM and GPU slots close to the socket.

Southbridge

Part of the motherboard's chipset and can also be known as the I/O Control Hub (ICH). Handles input from other devices such as BIOS, peripherals, PCI, and PCI-E cards, USB devices, then passes it to the Northbridge and then to the CPU.

Northbridge

Part of the motherboard's chipset and can also be known as the Memory Control Hub (MCH). Handles faster components that need more direct access and quick responses from the CPU such as RAM and GPU's

Single Sided RAM

RAM that can access both side of the memory chips at the same time, as if both sides were one larger single side. Back and forth from one side to the other.

Double Sided RAM

RAM that requires one side of the memory modules to fill up before moving to the second side. Double sided RAM fills up sequentially.

RAM

Random Access Memory - dynamic work area for the processor, like scrap paper. RAM is very fast access memory/storage but is cleared when there is no electricity so the storage is temporary or volatile. RAM is available in many sizes and varieties but comes in "sticks" with memory chips on them and get slotted into the motherboard of the system.

ROM

Read only Memory - instruction that are burnt into the chip, like a printed instruction sheet. Information is stored on the chip by being printed at the factory and the user cannot* change the information, no electricity required. *there are ways to do so but not easily done.

RCA

Red, white and yellow connectors that transmit both audio and video. The red and white connectors are for audio while the yellow is for composite video (low quality). Three pin connectors and may be found on higher end speakers that connect to computers or devices.

RAID

Redundant Array of Independent (Inexpensive) Disks - Available in various types, but all require multiple drives and will provide some benefit of data security (redundant copies), or faster read/write speeds. Keep in mind that all drive need to be the same capacity. RAID requires motherboard support or a RAID controller card to be implemented. If the Motherboard supports it then you will need to setup the arrays in the BIOS or UEFI. Any drives included in an array will be formatted in the process. There are software RAID controllers but they will require that the OS is available and functioning correctly, due to this point of failure hardware controllers are preferred.

RJ11

Register Jack 11, used for phone connections, such as landlines but also old modems for slow dial up internet. Has 4 conductors inside and a locking lever similar to Ethernet cables.

RJ45

Register Jack 45, also known as an Ethernet cable. Most common type of networking cable, has 8 color coded pairs of conductors, color and then a white + color wire. Has a locking lever. Used to connect most systems to a network, they come in many types and speeds known as Categories.

SD Cards

Secure Digital has 9 pins that are exposed. Comes in various form factors and has become the standard of small portable device storage for cameras and other small devices. SD cards have a slider that allows the card to be read only, protecting the data on the card from being overwritten. Variants of the SD card include Mini SD, Micro SD, and xD cards. SD cards also come in differing capacities such as HC, XC, UHS for higher capacity or fast write speeds. They come preformatted with FAT32 file system.

Serial ATA 3 (SATA 3 or SATA III)

Serial AT Attachment 3 - 7 pin internal connection that supports speeds of up to 6.0 Gbit/s

SIMM

Single inline memory module - memory chips are located on only one side of the RAM module. Older style and less common today.

Magnetic Tapes

Slowest type of media, but provides large capacities (Ex 500GB min with some at 6.25TB or larger) at fairly inexpensive price points. Tapes are used in enterprise solutions for the most part. Data stored on tape drives are stored, read and written sequentially like VHS or cassette tapes. Tape drives are secure and good for long term offsite storage and capable of many re-writes. There are tape readers/drives that can read/store one tape at time and there are libraries that can hold 40 tapes at a time and have mechanical arm swap out tape drives from one of their two drives.

ITX

Small form factor computer case, this motherboard can be used for thinclients, home theater PC's and other smaller systems. Max out at 4 expansion slots most times. (Ex. 9" x 7.5")

SO-DIMM

Small outline dual inline memory module - half the size of DIMM and found in smaller devices such as laptops, NUC's and miniITX boards.

Mini ITX

Smaller than ITX, motherboard designed for basic computing tasks and likely used for thinclients. Systems built with these are functional but won't be the fastest system. No moving parts and most times won't even have a hard drive, they will use smaller flash storage and only 1 expansion slot max. (Ex. 6.7" x 6.7")

802.11a

Speeds of up to 54Mbps at a range of 120 meters and operates on the 5GHz spectrum using FHSS.

Flash based storage

Storage devices that have no moving parts at all which allow for less chance to break, less heat, quieter, faster data rates and smaller sizes. Flash storage is found in flash drives, SD cards, eMMC cards, Compact Flash, storage in smartphones and SSD's (Higher quality and performance.) Flash storage is made up of a series of chips rather than a spinning platter and GB for GB will be more expensive than traditional mechanical drives.

RAID 0

Striping - Treats all disks as one large disk with a capacity of all drives combined. Data is then written as stripes across all of the disks in the array allowing for fast speeds since there are more heads that can read/write their piece of the data simultaneously. Has no redundancy and if one drive fails, all data is lost since each drive contains a piece of all of the data stored and then files are corrupted when a piece of their data is missing. Can be commonly used in graphics and video environments for better render times.

RAID 10 (or 1+0)

Striping Mirrors - Disks are mirrored in two blocks, then data is stripped across both drives in the block. Data is then mirrored to the other block of drives in the same stripped manner. This type of array requires at least 4 drives. This type of array provides speed and redundancy and allows for more than one drive to fail before losing data.

RAID 5

Striping and Parity - The type of array requires a minimum of 3 drives. Data is striped across the drives for extra speed, similar to RAID 0, but 1 drive stores parity information. The parity information, plus the data stored on the other disks allow for one drive to fail and retain all data, similar to RAID 1 but with some speed benefit. In this array only one drive can fail before loosing data, unless you have the maximum of 32 drives, then you can have 2 drives fail before any data is lost.

Heatsink or Cooler

Structure that sits on top of a component that is made out of very conductive materials used to draw heat away from the component to allow it to not throttle it's performance due to heat issues. Most common/popular use if for CPU's, there are various types including custom water/liquid (oils) cooling, all-in-one water/liquid cooling units, air cooling heatsink towers and stock heatsinks that all modern CPU's come with. Higher end systems or overclocked systems will require heavier duty solutions such as the water coolers or in sound sensitive environments.

SDRAM

Synchronous dynamic random access memory - allows the RAM to time itself based off of the system's bus allowing it to operate faster on a system with a faster system bus, allowing the RAM to no longer be the bottleneck.

Category 4 (CAT 4)

Token Ring, speeds up to 16Mbps and uses a RJ45 Connector.

xD Card

Type of SD card used by Olympus and Fujufilm in their digital cameras, was a proprietary standard and was not used in many devices. Slightly larger form factor and had 18 pins.

USB

Universal serial bus - Ubiquitous connector type with many different variants and speeds. Has a A end (Upstream - Computer 4 pin connector) and a B end (Downstream - printer, scanner, hard drive etc.) Typically supply 5 volts of power to a device. Created in 1996.

USB 3.1

Up to 10 Gbps still with the 3 meter (10 feet) range specification.

USB 1.1

Up to 12 Mbps 4 pin A connector and a max range of 3 meters (10 feet).

USB 2.0

Up to 480 Mbps 4 pin A connector and a max range of 5 meters (16 feet).

USB 3.0

Up to 5 Gbps - 4 pin A connector, 9 pin B connector, max range of 3 meters (10 feet). Typically indicated by blue connectors and the "SS" emblem standing for "super speed".

Compact Flash (CF)

Used by DSLR cameras, Cisco Switches and Routers and other devices. Compact flash is fairly fast at 80-200 Mbps and has no moving parts. Covered pin connectors.

Category 1 (CAT 1)

Used by telephone companies for DSL, supports speeds of up to 100 Mbps. Has an RJ45 connector.

1/8" Jack or 3.5mm Jack

Used primarily in audio, and is how most headphones and speakers connect to a system. There are different varieties such as mono, stereo, microphone support or even low quality video. You can tell what type of cable you have based on the number or rings on the plug, one is mono, 2 is stereo and 3 can be either microphone support or video. Range on these cables is pretty long.

RAID 1 Duplexing

Using two drives and two RAID controllers to ensure that data remains accessible even if one RAID controller fails. Duplexing is more expensive since it requires buying two of each component but is very good for data security.

VGA

Video Graphics array (DB15) - 15 pin connector used to output analog video signal in a waveform.

Bluetooth

Wireless medium range connection on the 2.4GHz spectrum. Comes in different ranges, speeds and power consumption based on the version. Most devices will stay connected for about 10 meters. Devices must pair before communicating. This standard is found in many devices today and can automatically reconnect if items have been pair before. Speeds range from 1 Mbps on v1.2 all the up to 24Mbps starting in v3.

802.11 (WiFi)

Wireless standard that is most commonly used by people to connect to a network wirelessly. Comes in many versions that support both 2.4GHz and 5GHz spectrum versions, but has the best range and bandwidth.

802.11ac

Wireless standard that supports up to 1.3Gbps on each radio at a range of about 250 meters on the 5GHz spectrum.

802.11g

Wireless standard that supports up to 54Mbps at a range of 140 meters on the 2.4GHz spectrum but uses OFDM rather than FHSS for the first time for less interference on the 2.4GHz spectrum.

802.11n

Wireless standard that supports up to 600Mbps at a range of 250 meters and can operate on both the 2.4GHz and 5GHz spectrums for more flexibility.

CD-RW

Writable and re-writeable compact disc that allowed data to be written to the disc and that data to be written over to store new data. Same capacity as the CD-R at 700MB, and required a CD drive to access the data.

DVD-RW

Writable and re-writeable digital versatile disc that allowed data to be written to the disc and that data to be written over to store new data. Same capacity as the DVD-R at 4.7GB, and required a DVD drive to access the data.