Microsoft Binary Format

In <a href="/facts/Computing/Kghtm9fX">computing</a>, Microsoft Binary Format (MBF) is a format for <a href="/facts/Floating-point/eIckahxe">floating-point</a> numbers which was used in <a href="/facts/Microsoft/nGIDDXdx">Microsoft</a>'s <a href="/facts/BASIC/VYMl5TmA">BASIC</a> languages, including <a href="/facts/MBASIC/Ac4zEe29">MBASIC</a>, <a href="/facts/GW-BASIC/3XcQtD2e">GW-BASIC</a> and <a href="/facts/QuickBASIC/pfbnC5RX">QuickBASIC</a> prior to version 4.00.
There are two main versions of the format. The original version was designed for memory-constrained systems and stored numbers in 32 bits (4 bytes), with a 23-bit <a href="/facts/Significand/JFCVyTz4">mantissa</a>, 1-bit sign, and an 8-bit <a href="/facts/Exponent/pac6QY2g">exponent</a>. <a href="/facts/Microsoft_BASIC/SuctFIyc">Extended (12k) BASIC</a> included a double-precision type with 64 bits.
During the period when it was being ported from the <a href="/facts/Intel_8080/32FvNTcD">Intel 8080</a> platform to the <a href="/facts/MOS_6502/q9YLwkzm">MOS 6502</a> processor, computers were beginning to ship with more memory as a standard feature. This version was offered with the original 32-bit format or an optional expanded 40-bit (5-byte) format. The 40-bit format was used by most <a href="/facts/Home_computer/CDEPVd1T">home computers</a> of the 1970s and 1980s. These two versions are sometimes known as "6-digit" and "9-digit", respectively.
On <a href="/facts/Personal_Computer/koaYfNce">PCs</a> with <a href="/facts/X86/Kypq5fgu">x86</a> processor, <a href="/facts/QuickBASIC/pfbnC5RX">QuickBASIC</a>, prior to version 4, reintroduced the double-precision format using a 55-bit mantissa in a 64-bit (8-byte) format. MBF was abandoned during the move to QuickBASIC 4, which used the standard <a href="/facts/IEEE_754/dD3e7zAl">IEEE 754</a> format, introduced a few years earlier.

Microsoft Binary Format open-in-new

Microsoft Binary Format