Timeline of Binary Prefixes - 1960s

1960s

1960

The 11th Conférence Générale des Poids et Mesures (CGPM) announces the Système International d'Unités (SI) and adds prefixes giga, and tera, defined as 109 and 1012

May

• U.S. Patent 3,214,691 Frequency Diversity Communications System is filed on May 13, 1960:
  • "In actual construction, the delay line, which provides a total delay from one end to the other of one baud (10 microseconds for a 100 kilobit per second information rate), may be fabricated from lumped parameter elements, i.e., inductors and capacitors, in a well-known manner."
  • "At a 100 kilobit per second information rate, both mark and space signals will generally be transmitted in any 0.0001 sec, interval, and therefore this requirement is easily met with conventional resistors and capacitors."

October

• Gruenberger, Fred; Burgess, C. R.; Gruenberger, Fred (October 1960). "Letters to the Editor". Communications of the ACM 3 (10). doi:10.1145/367415.367419.
  • The 8K core stores were getting fairly common in this country in 1954. The 32K store started mass production in 1956; it is the standard now for large machines and at least 200 machines of the size (or its equivalent in the character addressable machines) are in existence today (and at least 100 were in existence in mid-1959).

1955–1961

• A search of the Computer History Museum's Stretch collection of 931 text documents dated from September 1955 through September 1961 shows no usage of k or K to describe main storage size.

1961

• Gray, L; R Graham (1961). Radio Transmitters. New York: McGraw-Hill. ISBN 0-07-024240-2. "In the case of the transmission of business-machine or telemetered data, it is more usual to express the speed in bits or kilobits (1,000 bits) per second."
  • Quoted in OED as first instance of "kilobit", though "it is more usual" suggests it is already in common use (see timeline entry for 1957)

February 17

• Described device contains 512 words, 24 bits each (=12,288 bits)

September

• "It is no longer reasonable to spend as much time to transmit an 80 bit address as 12 kilobits of message information-a 1500 to 1 ratio.... We have theoretically and experimentally proved that speech can be compressed from the straightforward requirement for 48 kilobit PCM channel capability to 2400 bits by the application of the Dudley syllabic vocoder."

October

• The IBM 7090 Data Processing System (a binary machine), Additional Core Storage (65K means "approximately 65000")
  • "The Additional Core Storage feature for the IBM 7090 Data Processing System provides a second IBM 7302 Core Storage, increasing the capacity of main storage by 32,768 words. The block of storage represented by both 7302 units is referred to as "main storage unit."
  • "Additional core storage provides two methods of using main storage: (1) The 65K mode—the computer program is enabled to address both of the main storage units, and (2) the 32K mode—the computer program is able to address only one storage unit, so that main storage capacity available to that program is effectively 32,768 words."
• The IBM 1410 Data Processing System, which used modified decimal addressing, uses decimal arithmetic for powers of ten, without prefixes
  • "Core storage units are available in 10,000-, 20,000- or 40,000-character position capacities."
  • "The matrix switch makes it possible to address any one of the 100 X-drive lines (in a 10K core array)."
  • "The 40K core array requires 40,000 valid five-position addresses from 0,000 to 39,999."
  • "This operation check detects errors in programming that cause invalid addresses. Examples: 40,000-and-above on a 40K core array; 20,000-and-above on a 20K core array. On a 10K core array, invalid addresses are detected by the address-bus validity check."

1962

• A reference to a "4k IBM 1401" meant 4,000 characters of storage (memory).

1963

August

• Ludwig uses kilobit in the decimal sense
• DEC Serial Drum Type 24
  • "Drums are equipped to store either 64, 128, or 256 data blocks, providing a memory capability of 16384, 32768, or 65536 computer words" (no abbreviations)

November

• Honeywell 200 Summary Description
  • "The main memory is a magnetic core ... The memory unit supplied as part of the basic central processor has a capacity of 2,048 characters, each of which is stored in a separate, addressable, memory location. This capacity may be expanded in modular increments by adding one 2,048-character module and additional 4,096-character modules."
  • "Random access disc file and control (disc capacities of up to 100 million characters are available.)"
  • "Up to eight drum storage units can be connected to the Model 270 Random Access Drum Control. Each drum provides storage for 2,621,441 characters, allowing a total capacity of approximately 21 million characters."

1964

• Gene Amdahl's seminal April 1964 article on IBM System/360 used 1K to mean 1024.
• Leng, Gordon Bell, et al., use K in the binary sense:

"The computer has two blocks of 4K, 18-bit words of memory, (1K=1024 words), attached to its central processor"

• Falkin, Joel; Savastano, Sal (May 1963). "Sorting with large volume, random access, drum storage". Communications of the ACM archive 6 (5): 240–244. doi:10.1145/366552.366580. "The Teleregister Telefile data processor includes drum storage whose capacity is far in excess of the requirements for sorting. ... The Telefile data processor provides 16,000 positions in memory, each position storing one binary coded decimal character. A floating accumulator arrangement allows the accumulator to contain any field in memory from 1 to 100 characters in length. All indexing is accomplished programmatically. Input and output tape blocking is fixed at 300 characters per block."

• IBM Data Processing Division press release distributed on April 7, 1964.
  • "System/360 core storage memory capacity ranges from 8,000 characters of information to more than 8,000,000."
• IBM 7090/7094 Support Package for IBM System/360 – November
  • "An IBM 1401 Data Processing System with the following minimum configuration is also required: 1. 4K positions of core storage" U.S. Patent 3,317,902 – ADDRESS SELECTION CONTROL APPARATUS – Filed April 6, 1964
  • 'To facilitate understanding of the invention, the main storage area has been illustrated as being of 8K capacity; however, it is to be understood that the main storage area may be of larger capacity (e.g., 16K, 32K or 64K) by storing address selection control data in bit positions "2," "1" and "0" of M register 197, respectively.'

1965

• "Each IBM 2315 disk cartridge can hold the equivalent of more than one million characters of information." IBM 1130 Press Release, February 11, 1965
• Wilkes, M.V. (April 1965). "Slave Memories and Dynamic Storage Allocation". Electronic Computers, IEEE Transactions on. EC-14 (2): pg. 270–271. doi:10.1109/PGEC.1965.263967. "One method of designing a slave memory for instructions is as follows. Suppose that the main memory has 64K words (where K=1024) and, therefore, 16 address bits, and that the slave memory has 32 words and, therefore, 5 address bits."
• IBM 1620 CPU Model 1 (a decimal machine) System Reference Library, dated July 19, 1965, states:
  • "A core storage module, which is 20,000 addressable positions of magnetic core storage, is located in the 1620. Two additional modules are available ... Each core storage module (20,000 positions) is made up of 12 core planes as shown in Figure 3. Each core plane contains all cores for a specific bit value."

1966

• U.S. Patent 3,435,420 CONTIGUOUS BULK STORAGE ADDRESSING is filed on January 3, 1966
  • 'Note that "K" as used herein indicates "thousands." Each storage location in the present embodiment includes 64 data bits and 8 related parity bits, as described herein.'
  • "Thus, if only storage unit 1A were provided, it would contain addresses 0 through 32K; storage IB would include addresses between 32K and 64K, storage 2A would contain addresses between 64K and 96K, ..."

1968

• A Univac 9400 disc based computer system ... "can have 2–8 8411 drives for 14.5–58 megabytes capacity. The 8411 has a transfer rate of 156K bytes per second." using megabytes in a decimal sense

March

• Donald Morrison proposes to use the Greek letter kappa (κ) to denote 1024 bytes, κ2 to denote 1024×1024, and so on. (At the time, memory size was small, and only K was in widespread use.)

June

• Wallace Givens responded with a proposal to use bK as an abbreviation for 1024 and bK2 or bK2 for 1024×1024, though he noted that neither the Greek letter nor lowercase letter b would be easy to reproduce on computer printers of the day.

October

• Bruce A. Martin further proposed that the prefixes be abandoned altogether, and the letter B be used as a binary exponent, similar to E notation, to create shorthands like 3B20 for 3×220 = 3 MiB

1969

• IBM 1401 (a decimal machine) Simulator for IBM OS/360
  • "1401 features supported are advanced programming, sense switches, tapes, multiply, divide, 16K core, and all standard instructions except Select Stacker."
  • "1401 core is simulated by 16,000 bytes of S/360 core obtained dynamically."
  • "Enough core must be available to allow at least 70K for a problem program area. If tape simulation is not required, this core requirement may be reduced to 50K with the removal of the tape Buffer area."
• U.S. Patent 3,638,185 HIGH DENSITY PERMANENT DATA STORAGE AND RETRIEVAL SYSTEM is filed on March 17, 1969 earliest Google Patent search containing "kilobyte")
  • "The data word processor 606 handles the inflow and out-flow of byte-oriented input/output data and interleaved signals at a rate of, for example, 500 kilobytes per second. Instruction processing rates of four to eight per microsecond are required for such a data flow."
• U.S. Patent 3,618,041 Memory Control System is filed on October 29, 1969
  • "FIG. 2a shows a practical example of an operand address which consists of, for example 24 bits. It is assumed herein that each block includes 32 bytes, each sector includes 1 kilobyte, the buffer memory 116 includes 4 kilobytes, and read data is represented by one double word or 64 bits, as one word in this case consists of 32 bits."
• IBM System/360 Component Descriptions (IBM 2314 Direct Access Storage Facility)
  • "Each module can store 29.17 million bytes or 58.35 million packed decimal digits ... total on-line storage capacity is 233.4 million bytes"
• "Each 11-disc pack (20 surfaces) has a storage capacity of 29 megabytes; maximum storage capacity with the largest version using a ninth drive as a spare) is 233,400,000 bytes."
• DEC PDP-11 (a binary addressed machine) Handbook
  • "PDP-11 addressing modes include . . . and direct addressing to 32K words" (Page 2) This appears to be the only use of K in this manual, though; elsewhere sizes are spelled out in full. Contrast the 1973 PDP-11/40 Manual, which defines K as 1024. (Below)
• "... each removable disc has a capacity of 2.3 million bytes or 3.07 million 6-bit characters. Up to four drives can be attached to a single controller, resulting in a total storage capacity of 9.2 megabytes." Usage of million and mega in decimal sense to describe HDD.