Advanced Operating System (MEMORY)
Assignment no 2
Submitted by:
Maryam Sajid
Numl-f21-20191 MSCS-2
Submitted to:
Dr. Saba Bashir
Memory Access Time:
The amount of time it takes the computer processor to read data from memory is known as access
time. Memory access times are measured in nanoseconds (ns), megahertz (MHz), or gigahertz (GHz).
CPUs and registers are still hundreds of times quicker than memory access. Moreover, the memory
access time is affected by the memory hierarchy's design, the size of blocks at each level, the
management rules applied for each level, and the time it takes to access information at each level.
Memory Access Speed:
Memory speed is measured in Megahertz (MHz). Memory clock is another way to assess memory
speed. DDR (Double Data Rate) doubles the data transfer rate. Most buses nowadays are 64 bits wide,
which means the bus can carry 8 bytes of data (64 bits/8 = 8 bytes). How can you figure out how much
data your memory can hold in a second? When you multiply 8 Bytes (64bits' Bus) by DDR 333 (which
is actually 166MHz x 2), you get 2656MB/sec.
Memory Size:
The storage unit's memory unit is the amount of data that can be stored. Bytes are used to measure
the storage capacity. Memory capacity affects a device's performance and the efficiency of its
input/output processes.
Memory block:
A "memory block" is a chunk of memory that is connected together. A memory block is allocated using
the malloc(size t size) method. The size specifies how big the block should be (in chars).
There are three aspects to the memory block. The memory address is loaded into the memory address
register in the first function (MAR). The memory data register's second job is to either read from or
write to the memory (MDR). The memory's final function, or aspect, is to store the programme that
will be executed by the processor. In the VHDL model, we'll accomplish this by storing programme
values in a constant array.
Block Size:
The size of the blocks used by the UNIX kernel to read or write files is known as the logical block size.
The logical block size differs from the physical block size in most cases. Physical blocks are typically
512 bytes in size, which is the smallest block that the disc controller can read or write. By default, the
logical block size is set to the system's page size.
Register Size:
Number of bits a processor can handle in a register The word size specifies how much data the
computer can handle at any one time. A larger computer is more powerful. Purchase a new CPU to
increase. Registers with 16 bits Registers with 32 bits Registers with 64 bits.
Register Access Speed:
A traditional scalar CPU register can only hold one data element (a word) or address at any given time.
Cache Access Time:
Cache is a random-access memory used by the CPU to reduce the average time taken to access
memory. The best-case memory access time (ignoring cache controller overhead) is tcache, while the
worst-case access time is tmain. Given that tmain is typically 50 to 75 ns, while tcache is at most a few
nanoseconds, the spread between worst-case and best-case memory delays is substantial.
Size of Cache
Cache is graded as Level 1 (L1), Level 2 (L2) and Level 3 (L3): L1 is usually part of the CPU chip itself and
is both the smallest and the fastest to access. Its size is often restricted to between 8 KB and 64 KB.