Memory

        Memory is a part of the computer where a user can store documents, applications and any sort of data. Memory can be put in the memory slot located on the motherboard inside a system unit. The term memory indentifies the data storage that comes in a form of chips, and the word storage is used for memory that exists on tapes or disks. The rerm memory is usually used as a shorthand for physical memory, which refers to the actual chips capable of holding sata. Some computers also use virtual memory, which expands physical memory obto a hold disk.
        There are different types of memory. First is the RAM (random access memory). It is the same as the main memory. The term RAM refers ti read and write memory, that is a user can both write data into RAM and read data from RAM. This is contrast ROM, which permits you only to read data. Most RAM is volatile, which means that it requires a steady flow of electricity to maintain its contents. As soon as the power is turned off, whatever data was in RAM is lost.
          The second type of memory is the ROM (read only memory). Computers almost always contain a small amount of read-only memory that holds inatructions for starting up the computer. Unlike RAM, ROM cannot be written to.
           The third type of memory is the PROM (programmable red only memory). It is a memory chip on which a user can store a proframs. But once the PROM has been used, you cannot wipe it clean and use it to store something else.
            The fourth  type of memory is the EPROM (erasable programmable read only memory). It is a special type og PROM that can be erased by exposing it to ultraviolet light. And the last type od memory is the EEPROM (electrically earsable prigrammable read only memory). It is a special type of PROM that can be erased by exposing it to an electrical charge.
             Main memory is often associated wirh adressable semiconductor memory. A semiconductor memory is an integrated circuits consisting of silicon-based transistors, used for primary storagebut also other pusposes in computers and other digital electronic devices. There are two main types of semiconductor memory and it is the volatile  and the non-volatile . Most semiconductors memory is organized into the memory cells. The memory cells are grouped i to woods of fixed words length, amd each word can be accessed by a binary addresses.
        The volatile memory is a computer memory that requires power to maintain the stored information. Most modern semiconductor volatile memory is either static RAM (SRAM) or dynamic RAM (DRAM). SRAM retains its contents as long as the power is connected and easy for intefacing. DRAM is more complicated for intefering and control, needing regular represent cycle to prevent losing its content. SRAM is not worthwhile for desktop system memory, where DRAM dominates, but is used for their cache memories.
        The non-volatile memory is computer memory that can retain the stored information even when not powered. Examples of non-volatile memory includes read-only memory , flash memory, most types of magnetic computer storage devices, optical discs, and early computer storage methods such as paper tape and punched cards.
         Computer memory operates at a high speed, fpr example the random access memory or the RAM , as the distinction from storage that provides slow-to-access program and data storage but offers higher capacities. The contents stored in the computer memory can be transferred to secondary memory using a memory management technique which is called the Virtual memory.
          Virtual memory is a system where all physical memory is controlled by the operating system. The operating system will decide what physical location to place the memory in. One of its advantages is that computer programmers no longer need to worry about where the memory is physically stored ar whether the users computer will have enough memory. Vortual memory systems usually include protected memory. Protected memory is a system where each program is given an area of memory to use and is not permitted to go outside that range.
          Use of protected memory greatly enhances both of the reliability and security of a computer system. Without protected memory it is possible that the bug in one program will alter the memory used by another program. This will cause the program to run off of currupted memory. If the operating system's memory are corrupted the entire computer system may crashed and need to be rebooted.
          The next significant advance in computer memory came with acoustic delay line memory which is developed by J. Presper Eckert. The two alternatives to the delay line are the Williams tube and Selectron tube. Both are using electron beams in glass tubez as means of storage. Fred Williams invented the Williams tube which would be the first random access compiter memory. The Williams tube is proven that it is more capacious than the Selectron tube. The Selectron tube was limited to 256 bits, while the Williams tube could store thousands and less expensive.
      Proper management of memory is vital for a computer system to operate properly. Modern operating system have complex systems to properly manage mempry. Failure to do so can lead to bugs, slow performance, and at worst case, takeover by viruses and malicious software. A memory leak occurs when a program requests memory from the operating system and never returns the memory when its done with it. A program with this bug will gradually requires more and more memory until the program fails as it runs out.
       A buffer overflow means that a program write data to the end of its allocated space and then continues to write data to memory that has been allocated for other purposes. This way results in erratic program behavior  including memory occurs errors.

Classification

                   States of matter

            Matter is a material substance that occupies space, has mass and is composed predominantly of atoms consisting of protons, nuetrons and electrons that constitutes the observable universe, and that is interconvertible with energy. A sample of matter can be gas, a liquid, or a solid. These three forms of matter are called the states of matter. These states of matter are classified to its volume or shape.
             A gas or also known as vapor has no fixed volume or shape. It conforms to the volume and shape of its container. A gas can be compressed to occupy a smaller volume, or it can expand to occupy a larger one.
             A liquid has a distinct volume independent of its container, but it has no specific shape. It assumes the shape of a portion of the container that it contains.
             A solid has both a definite shape and a definite volume. In addition, solid is rigid.