-2

Secondary storage mediums are always divided into sectors, but if a file is placed on a secondary storage medium, most likely, part of the file will partially fill up a sector and another file will not be able to store itself in that partially filled up sector. Hence if secondary storage mediums are divided into sectors, then less data can be stored versus if the secondary storage medium was not divided into sectors. Then what is the philosophy of the sector system?

Does this philosophy carry over in terms of primary storage and how they are allocated into blocks of 8 bits?

Improve this question
3
  • 1
    "Secondary storage mediums are always divided into sectors" -- Your premise is false. Magnetic tape does not use sectors. Mass storage is addressable by blocks. Sectors would be an attribute of the physical medium. FWIW there is always a degree of inefficiency in storage. The value of 1 in a 32-bit word wastes 31 bits.
    – sawdust
    Nov 11, 2017 at 0:08
  • Possible duplicate of What are disk sectors for? and Downsides of a small allocation unit size
    – sawdust
    Nov 11, 2017 at 0:23
  • There are a number of technologies related to how to encode spinning circular media. sectors are one early compromise that solved the problem with some serious limitations, which are made less glaring by more recent technologies. that's the story of computer science and engineering. C-H-S is a valid way to assign addresses to a cylindrical array but not without flaws. Its not unlike how we mask analog signals with square waves to ignore most of the data therein, focusing only on whether it indicates a zero or a one.
    – Frank Thomas
    Nov 11, 2017 at 6:45

1 Answer 1

Reset to default
1

Then what is the philosophy of the sector system?

It takes space to store the freelist of a filesystem. If blocks were a byte in size then it would take 11% of the space on the medium to store the freelist. There are very few, if any, situations where this much guaranteed usage would be useful.

Additionally, the use of blocks allows addressing of the medium to use fewer bits. 1 TiB requires 41 bits to address at the byte level, but only 29 bits with a 4kiB block size.

Does this philosophy carry over in terms of primary storage and how they are allocated into blocks of 8 bits?

Primary storage is divided into pages, with the size of a page dependent on both the system architecture and the operating system in use.

Improve this answer
1
  • There's also the fragmentation problem. The smaller your storage units the bigger the fragmentation issue becomes.
    – Loren Pechtel
    Nov 11, 2017 at 0:32

Not the answer you're looking for? Browse other questions tagged or ask your own question.