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concept of assigning a reference of zero to the first address of a word on a page in memory) as the convention is frequently used by computer technologists. The convention can be contusing for the beginner who fails to remember that the physical quantity is one more than the reference designation. The convention of labeling the first physical position as zero makes much more sense once the reader learns to think in terms of the binary

The accumulator simply holds a number-it adds and subtracts-and "rotates" its contents.

259th PHYSICAL WORD IN MEMORY HAS AN ABSOLUTE ADDRESS OF 258

512th PHYSICAL WORD IN MEMORY H AS AN ABSOLUTE \DD RESSO! SEi

S ] Jih PHYSICAL WORD IN MEMORY HAS AN ABSOLUTE ADDRESS OF; 512

ABSOLUTE ADDRESS IN THE PROGRAM t OUN II1R

1024th PHYSICAL WORD IN Ml MORY H AS AN ABSOLUT f ADDRESS OF: 1023

numbering system and thoroughly realizes thai the ''zero1' referred to so frequently in computer work when discussing actual operations actually represents a physical state (the status of an electronic switch) and does not necessarily imply the mathematical notion of "nothing." The concept of assigning a bit designation to the positions of the cells within the accumulator will allow the reader to follow explanations of various accumulator operations.

One of the most fundamental and most often used operations of an accumulator is for it to simply hold a number while the CPU obtains a second operator. In an 8008 type of machine the accumulator can be 'loaded" with a value obtained from a location in memory or one of the "partial accumulators." 11 can then hold this value until it is time to perform some other operation with the accumulator. (It will become apparent later that the accumulator of an 8008 can also receive information from external devices.)

Perhaps the second most often used operation oi an accumulator is to have it perform mat he ma tj cat operations such as addition or subtraction with the value it contains at the time the function is performed and the contents of a memory location or one of the "partial accumulators." Thus if the accumulator contained featuring MITS Altair Computers

ByteTronics is the hobbyist's dream come true, full ser. ce cc r c -iter store fe :Hirino the full line of Altair Computer products backed by the most complete technical service available

The prices at ByteTronics are MiTS factory prices ond most items are available on an off-the-shelf basis.

ByteTronics sponsors the local Altair Users Group of East Tennessee and EfyleTronics is interested.in communicating with computer hobbyists throughout the world-

If you have a question about Altair hardware (whether or not you are ByteTronics customer), we will put you directly in touch with our Technical Director. Hugh Huddelston Hugh is an expert troubleshooter who has a thorough knowledge of each portion of each Altair board And he can answer all your questions about custom interfacing

If you have questions about software o if ,-ou .. int ior e custom programming our Software Director. Johnny Reed, is the expert who can take care of your needs Johnny has had years of programming experience, and he is familiar with Altair BASIC, assembler and machine language programming

If you have questions about the availability of a MITS product or its price or specifications, we will let you talk to Bruce Seals, our Director of Marketing.

At ByteTronics we want you to understand your Altair and we are willing to give you all the technical support you need.

ByteTronics sells computers. ByteTronics sells service.

For more information, visit our store in Knoxviile—or write or coll us. We want to hear from you,

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