Search results
Results from the WOW.Com Content Network
File size is a measure of how much data a computer file contains or how much storage space it is allocated. Typically, file size is expressed in units based on byte . A large value is often expressed with a metric prefix (as in megabyte and gigabyte ) or a binary prefix (as in mebibyte and gibibyte ).
Thus, a representation that compresses the storage size of a file from 10 MB to 2 MB yields a space saving of 1 - 2/10 = 0.8, often notated as a percentage, 80%. For signals of indefinite size, such as streaming audio and video, the compression ratio is defined in terms of uncompressed and compressed data rates instead of data sizes:
With the standard hard disk sector size of 512 bytes, this gives a maximum of 32 KB cluster size, thereby fixing the "definitive" limit for the FAT16 partition size at 2 GB for sector size 512. On magneto-optical media, which can have 1 or 2 KB sectors instead of 0.5 KB, this size limit is proportionally larger.
34,359,738,368 bits (4 gibibytes) – maximum addressable memory for the Motorola 68020 (1984) and Intel 80386 (1985), also the volume size limit for the FAT16B file system (with 64 KiB clusters) as well as the maximum file size (4 GiB-1) in MS-DOS 7.1-8.0. 3.76 × 10 10 bits (4.7 gigabytes) – capacity of a single-layer, single-sided DVD: 2 36
For most DOS-based operating systems, the maximum cluster size remains at 32 KB (or 64 KB) even for sector sizes larger than 512 bytes. For logical sector sizes of 1 KB, 2 KB and 4 KB, Windows NT 4.0 supports cluster sizes of 128 KB, while for 2 KB and 4 KB sectors the cluster size can reach 256 KB.
Because file size references are stored in eight instead of four bytes, the file size limit has increased to 16 exabytes (EB) (2 64 − 1 bytes, or about 10 19 bytes, which is otherwise limited by a maximum volume size of 128 PB, [nb 2] or 2 57 − 1 bytes), raised from 4 GB (2 32 − 1 bytes) in a standard FAT32 file system. [1]
In this convention, one thousand and twenty-four megabytes (1024 MB) is equal to one gigabyte (1 GB), where 1 GB is 1024 3 bytes (i.e., 1 GiB). Mixed 1 MB = 1 024 000 bytes (= 1000×1024 B) is the definition used to describe the formatted capacity of the 1.44 MB 3.5-inch HD floppy disk , which actually has a capacity of 1 474 560 bytes .
On modern systems, all versions of Microsoft Windows including the newest (as of 2019) Windows 10 divide by 1024 and represent a 65,536-byte file as "64 KB". [9] Conversely, Mac OS X Snow Leopard and newer represent this as 66 kB, rounding to the nearest 1000 bytes. [15] File sizes are reported with decimal prefixes. [16]