Camintonn CMV-4000 - Revision history

Jnc: avoid redir

2022-01-13T15:33:01Z

avoid redir

Jnc: Jnc moved page CMV-4000 to Camintonn CMV-4000 over redirect: naming sys

2020-12-14T00:47:31Z

Jnc moved page CMV-4000 to Camintonn CMV-4000 over redirect: naming sys

Jnc: +cat, +links

2018-12-11T02:28:35Z

+cat, +links

Jnc: Add links, avoid redirs

2018-07-18T12:28:20Z

Add links, avoid redirs

Jnc: copyedit

2016-09-10T13:32:31Z

copyedit

Jnc: A start - has chip info, at least

2016-09-09T23:03:30Z

A start - has chip info, at least

New page

The '''Camintonn CMV-1000''' and '''CMV-4000''' are a pair of [[QBUS]] memory cards, in [[DEC card form factor|quad]] QBUS card-size format, with capacities of 1 Mbyte and 4 Mbytes, respectively. They both use the same [[PCB]], and have capacities of 1 Mbyte when using 64Kx1 [[DRAM]]s, or 4 Mbytes (using 256Kx1 DRAMs).

==Configuration==

No original Camintonn documentation is currently available; configuration information will therefore provided here shortly.

==Repair==

Although documentation is currently known for this card, since this card has eight banks (i.e. it has a 8x18 array of xx64 or xx256 chips; i.e. to provide 16 bits wide plus byte parity, there are eight groups of 18 chips), it is sometimes possible to repair problems in one.

If one bank is picking or dropping bit(s), and the others are not, that meant that data paths were all OK, and it is a simple matter of finding the bad memory chip(s).

By pulling memory chips (luckily, they were socketed on the board of this type which was examined to create this page, so the process was fairly painless), it was possible to work out which bits are stored in which chips. (Unlike many memory cards, it's not semi-random.)

The card has 18 columns, labelled '0'-'7', 'P0', '8'-'15', and 'P1'. These are exactly like what they sound like: the 16 bits of a word, plus a parity bit for each byte. The exact bit to chip correspondence is:

{| class="wikitable"
! Bit !! Column
|-
| 01 || 0
|-
| ...
|-
| 0200 || 7
|-
| 0400 || 8
|-
| ...
|-
| 0100000 || 15
|}

Similarly, there are 8 rows of memory chips, labelled 'A' through 'H',
and these are the banks, with 'A' being that at the lowest address on
the card. The exact addresses are:

{| class="wikitable"
! Row !! colspan="2" style="text-align:center;" | Bank starting address
|-
| || CMV-1000 || CMV-4000
|-
| A || 0 || 0
|-
| B || 0400000 || 02000000
|-
| C || 1000000 || 04000000
|-
| D || 1400000 || 06000000
|-
| E || 2000000 || 10000000
|-
| F || 2400000 || 12000000
|-
| G || 3000000 || 14000000
|-
| H || 3400000 || 16000000
|}

{{PDP-11}}

@@ Line 54: / Line 54: @@
 | H || 3400000 || 16000000
 |}
 [[Category: QBUS Memories]]

@@ Line 11: / Line 11: @@
 If one bank is picking or dropping bit(s), and the others are not, that meant that data paths are all OK, and it is a simple matter of finding and replacing the bad memory chip(s).
-By pulling memory chips (luckily, they were socketed on the board of this type which was examined to create this page, so the process was fairly painless), it was possible to work out which bits are stored in which chips. (Unlike many memory cards, it's not semi-random.)
+By pulling memory chips (luckily, they were [[chip socket|socketed]] on the board of this type which was examined to create this page, so the process was fairly painless), it was possible to work out which bits are stored in which chips. (Unlike many memory cards, it's not semi-random.)
 The card has 18 columns, labeled '0'-'7', 'P0', '8'-'15', and 'P1'. These are exactly like what they sound like: the 16 bits of a word, plus a parity bit for each byte. The exact bit to chip correspondence is:
@@ Line 56: / Line 56: @@
 {{PDP-11}}

@@ Line 1: / Line 1: @@
-The '''Camintonn CMV-1000''' and '''CMV-4000''' are a pair of [[QBUS]] memory cards, in [[DEC card form factor|quad]] QBUS card-size format, with capacities of 1 Mbyte and 4 Mbytes, respectively. They both use the same [[PCB]], and have capacities of 1 Mbyte when using 64Kx1 [[DRAM]]s, or 4 Mbytes when using 256Kx1 DRAMs.
+The '''Camintonn CMV-1000''' and '''CMV-4000''' are a pair of [[QBUS]] [[main memory]] cards, in [[DEC card form factor|quad-size]] format, with capacities of 1M-[[byte]] and 4M-bytes, respectively. They both use the same [[printed circuit board|PCB]], and have capacities of 1M-byte when using 64Kx1 [[dynamic RAM|DRAM]] [[integrated circuit|chips]], or 4M-bytes when using 256Kx1 DRAMs.
 ==Configuration==
@@ Line 7: / Line 7: @@
 ==Repair==
-Although no documentation is currently known for this card, since this card has eight banks (i.e. it has a 8x18 array of xx64 or xx256 chips; to provide 16 bits wide plus byte parity, there are eight groups of 18 chips), it is sometimes possible to repair problems in one.
+Although no documentation is currently known for this card, since this card has eight banks (i.e. it has a 8x18 arrays of xx64 or xx256 chips, to provide 16 bits wide plus byte [[parity]]; there are eight arrays of 18 chips), it is sometimes possible to repair problems in one, if the problem is a faulty DRAM chip.
-If one bank is picking or dropping bit(s), and the others are not, that meant that data paths were all OK, and it is a simple matter of finding the bad memory chip(s).
+If one bank is picking or dropping bit(s), and the others are not, that meant that data paths are all OK, and it is a simple matter of finding and replacing the bad memory chip(s).
 By pulling memory chips (luckily, they were socketed on the board of this type which was examined to create this page, so the process was fairly painless), it was possible to work out which bits are stored in which chips. (Unlike many memory cards, it's not semi-random.)
@@ Line 31: / Line 31: @@
 |}
-Similarly, there are 8 rows of memory chips, labelled 'A' through 'H',
+Similarly, there are 8 rows of memory chips, labelled 'A' through 'H', and these are the banks, with 'A' being that at the lowest address on the card. The exact addresses are:
 {| class="wikitable"

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