Definition of "megabyte"

The IBM 2301 Drum Storage (Figure 20) provides random access storage of approximately 4 million bytes at a data rate of 1.2 megabytes per second.

1964, System/360 System Summary, IBM, page 27

This 70-megabyte data module contains fixed heads in addition to the normal access heads.

1973, Reference Manual for IBM 3340/3344 Disk Storage, IBM, page 3

One megabyte is 1,048,576 bytes. One megahertz, however is a million Hertz.

2003, Michael Meyers, Managing and Troubleshooting PCs, page 933

Defaults to 2 megabytes (2,097,152 bytes).

2004, Kerry Cox, Christopher Gerg, Managing Security with Snort and IDS Tools, page 92

By default, each log file [...] is exactly 5 megabytes (5,242,880 bytes) in size.

2006, Eriq Oliver Neale, Microsoft Small Business Server 2003 Unleashed, page 290