A slab or syllable is the primary unit of memory

Memory

In psychology, memory is an organism's ability to store, retain, and recall information and experiences. Traditional studies of memory began in the fields of philosophy, including techniques of artificially enhancing memory....

 in the NCR 315

NCR 315

The NCR 315 Data Processing System, released in January 1962 by NCR, was a second-generation computer. All printed circuit boards used resistor-transistor logic to create the various logic elements. It used 12-bit slab memory structure using core memory. The instructions could use a memory slab as...

 computer architecture

Computer architecture

In computer science and engineering, computer architecture is the practical art of selecting and interconnecting hardware components to create computers that meet functional, performance and cost goals and the formal modelling of those systems....

 from NCR Corporation

NCR Corporation

NCR Corporation is an American technology company specializing in kiosk products for the retail, financial, travel, healthcare, food service, entertainment, gaming and public sector industries. Its main products are self-service kiosks, point-of-sale terminals, automated teller machines, check...

. Having 12 data bit

Bit

A bit is the basic unit of information in computing and telecommunications; it is the amount of information stored by a digital device or other physical system that exists in one of two possible distinct states...

s and a parity bit

Parity bit

A parity bit is a bit that is added to ensure that the number of bits with the value one in a set of bits is even or odd. Parity bits are used as the simplest form of error detecting code....

, its size falls between a byte

Byte

The byte is a unit of digital information in computing and telecommunications that most commonly consists of eight bits. Historically, a byte was the number of bits used to encode a single character of text in a computer and for this reason it is the basic addressable element in many computer...

 and a typical word (hence the name, 'syllable'). A slab may contain three digits (with at sign

At sign

The at sign , also called the ampersat, apetail, arroba, atmark, at symbol, commercial at or monkey tail, is formally an abbreviation of the accounting and commercial invoice term "at the rate of"...

, comma

Comma (punctuation)

The comma is a punctuation mark. It has the same shape as an apostrophe or single closing quotation mark in many typefaces, but it differs from them in being placed on the baseline of the text. Some typefaces render it as a small line, slightly curved or straight but inclined from the vertical, or...

, space

Space (punctuation)

In writing, a space is a blank area devoid of content, serving to separate words, letters, numbers, and punctuation. Conventions for interword and intersentence spaces vary among languages, and in some cases the spacing rules are quite complex....

, ampersand

Ampersand

An ampersand is a logogram representing the conjunction word "and". The symbol is a ligature of the letters in et, Latin for "and".-Etymology:...

, point

Decimal separator

Different symbols have been and are used for the decimal mark. The choice of symbol for the decimal mark affects the choice of symbol for the thousands separator used in digit grouping. Consequently the latter is treated in this article as well....

, and minus

Plus and minus signs

The plus and minus signs are mathematical symbols used to represent the notions of positive and negative as well as the operations of addition and subtraction. Their use has been extended to many other meanings, more or less analogous...

 treated as digits) or two alphabetic characters. A slab may contain a decimal

Decimal

The decimal numeral system has ten as its base. It is the numerical base most widely used by modern civilizations....

 value from -999 to +999.

A numeric value contains up to eight slabs. If the value is negative then the minus sign is the leftmost digit of this row. There are commands to transform digits into alphanumeric characters or inverse. All these commands use the accumulator

Accumulator (computing)

In a computer's central processing unit , an accumulator is a register in which intermediate arithmetic and logic results are stored. Without a register like an accumulator, it would be necessary to write the result of each calculation to main memory, perhaps only to be read right back again for...

 which has a maximum length of eight slabs. To accelerate the processing the accumulator works with an effective length.

The NCR 315 was the follow-on to the NCR 304

NCR 304

The NCR 304, introduced in 1957, was National Cash Register 's first transistor-based computer. The 304 was developed and manufactured in cooperation with General Electric.Its follow-on was the NCR 315....

.