Difference between revisions of "DEC card form factor"

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Many different [[DEC]] computers (e.g. [[PDP-8]], [[PDP-10]], [[PDP-11]]) used a standard set of board sizes, in part because they all used [[FLIP CHIP]]s.
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Many different [[DEC]] computers (e.g. [[PDP-8 family|PDP-8]], [[PDP-10]], [[PDP-11]]) used a standard set of board sizes, in part because they all used [[FLIP CHIP]]s.
  
 
The original small '''standard length''' FLIP CHIPs (used in the PDP-8 and [[KA10]] PDP-10 processor) had a total board size of 4.93 inches (from the far end of the edge connector contacts, to the handle end of the board) by 2.437 inches (from one side to the other). From this basic size, a large array of other sizes was built up.
 
The original small '''standard length''' FLIP CHIPs (used in the PDP-8 and [[KA10]] PDP-10 processor) had a total board size of 4.93 inches (from the far end of the edge connector contacts, to the handle end of the board) by 2.437 inches (from one side to the other). From this basic size, a large array of other sizes was built up.
  
A board of the same width, but approximately twice as long (8.43 inches) was referred to an an '''extended length''' board; many later M-series FLIP CHIPs used this format. A board of the short length, but twice as wide (5.187 inches) was referred to as a '''double height'''  board; boards of this size are not common, but do exist. (The 'height' does not refer to the length, but to the width; this is because these board were usually mounted vertically, with the side edges on the top and bottom.)
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A board of the same width, but approximately twice as long (8.43 inches) was referred to an an '''extended length''' board; many later M-series FLIP CHIPs used this format. A board of the short length, but twice as wide (5.187 inches) was referred to as a '''double height'''  board; boards of this size are not common, but do exist.
  
Extended length boards came in multiples of two, four (10.457 inches) and six times the width of the small original board; these are usually called '''dual''', '''quad''' and '''hex''' height format boards.
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(The 'height' does not refer to the distance from the edge with the handles, to the edge with the contacts, but rather to the distance from one side edge to the other; this is because these board were usually mounted vertically, with the side edges on the top and bottom.)
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Extended length boards later came in multiples of two, four (10.457 inches) and six times the width of the small original board; these are usually called '''dual''', '''quad''' and '''hex''' height format boards.
  
 
Finally, as production processes improved, and leading signals from board to board became undesirable, even longer hex boards were introduced; these first appeared in the [[VAX-11/780]], and were called '''super hex''' boards within DEC.
 
Finally, as production processes improved, and leading signals from board to board became undesirable, even longer hex boards were introduced; these first appeared in the [[VAX-11/780]], and were called '''super hex''' boards within DEC.
  
==Edge connector contact identification==
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==Specifications==
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The mechanical specifications for single, dual and quad-height FLIP CHIP boards can be found in the [http://www.bitsavers.org/pdf/dec/handbooks/Digital_Logic_Handbook_1975-76.pdf Digital Logic Handbook 1975-76], p. 6-10.
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==See also==
  
The edge connector contact groups (often called 'rows', in DEC documentation) on the edge of a hex card are 'numbered' A-F, starting from the top (when the card is installed, vertically); this would be the right-hand edge, when the card is horizontal, with the component side up, and the connector 'fingers' '''toward''' the viewer.
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* [[DEC edge connector contact identification]]
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* [[FLIP CHIP]]
  
Within each row, the individual contacts are 'numbered' from the [[DEC Alphabet]]; those on the component side are further numbered '1', and those on the solder side, '2'. I.e. with the board in a horizontal position, as described above, the right-most contact on the top side (i.e. visible) would be identified as 'AA1'.
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[[Category: DEC Hardware]]

Revision as of 22:13, 17 October 2021

Many different DEC computers (e.g. PDP-8, PDP-10, PDP-11) used a standard set of board sizes, in part because they all used FLIP CHIPs.

The original small standard length FLIP CHIPs (used in the PDP-8 and KA10 PDP-10 processor) had a total board size of 4.93 inches (from the far end of the edge connector contacts, to the handle end of the board) by 2.437 inches (from one side to the other). From this basic size, a large array of other sizes was built up.

A board of the same width, but approximately twice as long (8.43 inches) was referred to an an extended length board; many later M-series FLIP CHIPs used this format. A board of the short length, but twice as wide (5.187 inches) was referred to as a double height board; boards of this size are not common, but do exist.

(The 'height' does not refer to the distance from the edge with the handles, to the edge with the contacts, but rather to the distance from one side edge to the other; this is because these board were usually mounted vertically, with the side edges on the top and bottom.)

Extended length boards later came in multiples of two, four (10.457 inches) and six times the width of the small original board; these are usually called dual, quad and hex height format boards.

Finally, as production processes improved, and leading signals from board to board became undesirable, even longer hex boards were introduced; these first appeared in the VAX-11/780, and were called super hex boards within DEC.

Specifications

The mechanical specifications for single, dual and quad-height FLIP CHIP boards can be found in the Digital Logic Handbook 1975-76, p. 6-10.

See also