USB Full Form, What is USB?

USB full form Universal Serial Bus.

The “Universal” means that the bus itself, and controllers for the bus don’t really care about what the data is, and only concern themselves with transmission of the data, and capabilities of hardware on both ends of transmission. RS-232 and LP both tended to bog down hardware on having to do VERY specific things with their data and how it is communicated, whereas USB is designed to abstract that through controllers that just want to know what’s going in and going out, simplifying the addressing and signaling requirements of hardware and driver designers significantly as they can just ignore signal implementation details.

The “Serial” is because the data is transmitted one piece at a time. This may seem like it would be slower than a parallel bus, and in theory it would be, but one of the biggest flaws in a parallel bus is that hardware has to be designed to input and output each bit on its own line, making it more complicated to design and more expensive in the end. Serial interfaces, especially USB, are very fast now despite having to shift bytes one bit at a time, normally.

The “Bus” is, well, because it’s a bus. It’s a common signal interconnect between hardware used to send and receive data. What’s nice about USB is that it’s a bus that extends itself externally from the computer in an addressable, tree-like manner, meaning multiple devices can connect via one physical port on the machine, and there should be no conflict. Arguably the old serial or parallel connections are not buses, as they weren’t really addressable beyond what port on the computer is used, though in theory a device and device driver could be written for those to make a sort of bus-like protocol. Typically the old standards were designed with the idea that ONE device used that connection and thus every signal going in and out was meant for that one device, which to me means they weren’t bus standards.

ROM Full Form, What is ROM?

ROM full form Read Only Memory.

The memory from which we can only read but cannot write on it, this type of memory is non-volatile. The information is stored permanently in such memories during manufacture. A ROM stores such instructions that are required to start a computer. This operation is referred to as bootstrap. ROM chips are not only used in the computer but also in other electronic items like washing machine and microwave oven.

Types of ROMs and their characteristics

MROM (Masked ROM)

The very first ROMs were hard-wired devices that contained a pre-programmed set of data or instructions. These kinds of ROMs are known as masked ROMs, which are inexpensive.

PROM (Programmable Read Only Memory)

PROM is read-only memory that can be modified only once by a user. The user buys a blank PROM and enters the desired contents using a PROM program. Inside the PROM chip, there are small fuses which are burnt open during programming. It can be programmed only once and is not erasable.

EPROM (Erasable and Programmable Read Only Memory)

EPROM can be erased by exposing it to ultra-violet light for duration of up to 40 minutes. Usually, an EPROM eraser achieves this function. During programming, an electrical charge is trapped in an insulated gate region. The charge is retained for more than 10 years because the charge has no leakage path. For erasing this charge, ultra-violet light is passed through a quartz crystal window (lid). This exposure to ultra-violet light dissipates the charge. During normal use, the quartz lid is sealed with a sticker.

EEPROM (Electrically Erasable and Programmable Read Only Memory)

EEPROM is programmed and erased electrically. It can be erased and reprogrammed about ten thousand times. Both erasing and programming take about 4 to 10 ms (millisecond). In EEPROM, any location can be selectively erased and programmed. EEPROMs can be erased one byte at a time, rather than erasing the entire chip. Hence, the process of reprogramming is flexible but slow.

The advantages of ROM are as follows −

·         Non-volatile in nature

·         Cannot be accidentally changed

·         Cheaper than RAMs

·         Easy to test

·         More reliable than RAMs

·         Static and do not require refreshing

·         Contents are always known and can be verified

OTP Full Form, What is OTP?

OTP full form One-Time Password

A one-time password (OTP), also known as one-time pin or dynamic password is a password that is valid for only one login session or transaction, on a computer system or other digital device. OTPs avoid a number of shortcomings that are associated with traditional (static) password-based authentication; a number of implementations also incorporate two-factor authentication by ensuring that the one-time password requires access to something a person has (such as a small keyring fob device with the OTP calculator built into it, or a smartcard or specific cellphone) as well as something a person knows (such as a PIN).

Advantages:

The most important advantage that is addressed by OTPs is that, in contrast to static passwords, they are not vulnerable to replay attacks. This means that a potential intruder who manages to record an OTP that was already used to log into a service or to conduct a transaction will not be able to abuse it, since it will no longer be valid. A second major advantage is that a user, who uses the same (or similar) password for multiple systems, is not made vulnerable on all of them, if the password for one of these is gained by an attacker. A number of OTP systems also aim to ensure that a session cannot easily be intercepted or impersonated without knowledge of unpredictable data created during the previous session, thus reducing the attack surface further.

OTPs have been discussed as a possible replacement for, as well as enhancer to, traditional passwords. On the downside, OTPs are difficult for human beings to manipulate. Therefore, they require additional technology to work.