from Van Snyder

Start with the units position It determines which 4k bank of memory is used

The tens position determines which, if any, index register is used.

Column K provides the value specified by the zone values.

The hundreds position determines position within a 4 k bank

 Addressing above 4k is actually simple. The zones on the high-order character are the low-order bits of the thousands. These would get set by overflows using ordinary 3-character arithmetic on a machine with 4k or less memory, which is why those machines don't need the MA instruction. The zones on the low-order character are the high-order bits of the thousands. So if you know the numeric part of the address character, it's easy to compute the thousands. Here's a little chart like the one I had on a scrap of card stock in my pocket in 1966 (much smaller than a spreadsheet), this time using Pierce's primary (business chain) ASCII encoding instead of the one from page 170 of A24-1403: ```Card | 1 2 3 4 5 6 7 8 9 0 Card Zone | Units | Hundreds Zone | Core 1 2 3 4 5 6 7 Row | Zone | none A B AB | 1 2 3 4 5 6 7 8 8 8 8 8 8 8 8 =====|=======|===================|================================= | none | 0 1 2 3 | 1 2 3 4 5 6 7 8 9 0 # @ : > { 0 | A | 4 5 6 7 | ^ / S T U V W X Y Z | , % ~ \ " 11 | B | 8 9 10 11 | - J K L M N O P Q R ! \$ * ] ; _ 12 | AB | 12 13 14 15 | & A B C D E F G H I ? . ) [ < } ``` Record mark is |, A82 in core but 0-2-8 punch since the 0 row can't simultaneously be used for the A zone and the zero digit ;-> The ^ is the alternate space, A-zone only, used for even-parity tape. On 1410, or 1401's that have the free RPQ (which number I have forgotten), it's a 2-8 punch, not a zero punch (which is numeric zero, encoded in core as A82). Maybe you could print each on a sheet of paper, laminate them, and cut them into shirt-pocket-size pieces.