Replacement punch unit for 1442 Card Reader/Punch arrives

CARD READER AND PUNCH FOR IBM 1130

The IBM 1130 system from the mid 1960s was a punched card batch oriented machine as were most of that time. It offered a couple of choices for printers and card readers, with the 2501 and 1442 being the two choices for card handling. 

2501 reader

1442 Reader/Punch

The 2501 solely reads cards, but does so at a high rate (1000 cards per minute) compared to the speed of the 1442 at 300 to 400 cards per minute.  The 1442, however, can also punch cards and thus some installations used it along with a 2501 just for the punching capability.

The 1442 is a good example of IBM leverage of machinery to support multiple computer systems. The basic read/punch mechanism, called SRP or Serial Read Punch, was used with the IBM 1050 communications system and with the IBM 1440 computer system in addition to the IBM 1130. 

The 1050 was remotely connected to a computer and could configure Selectric type printers, typewriters, paper tape readers and punches as well as the SRP. The paper tape punch from the 1050 system was also sold for use with the 1130 as the IBM 1055 and its reader as the IBM 1054 until replaced by a faster IBM 1134 reader - more leverage. 

The 1442 has a hopper where cards are stacked to be processed, a read station, a punch station and stackers to hold cards after they passed through the machine. The machine fed cards and read them at 300 to 400 cpm depending on the model of the 1442, but when punching it was much slower. Blank cards had to be fed past the read station before they reached the punch station. 

When punching, the machine would tightly grip the card using a set of wheels with a ceramic tire that has grit embedded into the surface. For each column the unit would punch while holding the card still, then the wheels would advance the card exactly one column further. 

When the the last column of a card that the program wanted to punch had completed, the machine would feed the completed card at the regular card feed/read speed out to the stacker. The speed of the punching process was measured in card columns per second, available at either 80 or 160 columns/second. Thus punching time was the sum of the time for the grab and punch slow speed movement plus the feed cycle at the high rate. 

For example, if we assume the slower model with 300 cpm read/feed and 80 columns/second for punching and are going to punch 30 columns of a card, the times involved are:

• 0.375 seconds to punch the first 30 columns of a card
• 0.200 seconds to feed the completed one out and the new blank one in
• Total time is thus 0.575 seconds, 1.74 cards per second or 104 cards per minute

A full 80 column card being punched would slow down to 50 cards per minute. If you had purchased the faster model 7 (400 cpm, 160 cols/sec) then the full 80 column card could be punched at the rate of about 92 cards per minute. 

In addition to its relatively slow rate, the 1442 chewed up CPU time as it depended on software to perform functions that were built into the controller logic of the 2501. The 2501 would store all 80 columns of data into core memory without requiring any software intervention. 

The 1442 reader would present an interrupt for each of the 80 card columns being read, then the software had to issue an XIO Read to pick up the data value of that column. An interrupt at the end of the read would present status but that is no different from the 2501. Punching also required interrupts and XIO Write for each column to be punched. 

DAMAGED PUNCH IN MY UNIT

My 1442 reader/punch had suffered damage to one of the two ceramic tire covered wheels that move cards during punching. I tried to fill in the arc that was broken off with UV hardening epoxy with sand embedded, but that was not successful and during all the manipulation to attempt that, the other wheel cracked. These are very brittle and easily damaged. 

SPARE FROM A MUSEUM IS A WONDERFUL SOLUTION

One of the museums that I have been sharing advice during a restoration of their 1130 system had several spare punch units in their collection and kindly offered to ship one to me. It was packed with extraordinary care to avoid any impact on those ceramic tire wheels even with the worst of the abuse that packages receive during shipment. 

The box arrived with almost no signs of trauma, very unusual for such shipments. Even better, the protective packaging worked perfectly and the punch unit was safe and intact inside! Once I have completed the restoration of the current 1130 for the System Source Museum and returned it, I will swap this punch into my 1442 and make sure it is working well. 

UPDATE ON MY PROJECT STATUS POST A BIT EARLIER

Once the current restoration 1130 system is returned to its owner, I will be receiving another IBM 1130 to restore on behalf of the Vintage Computer Federation and its InfoAge museum. My list had only included items currently in my shop that I was or would be working on. I omitted the VCF machine but that caused some confusion from those who knew I was going to work on it. 

While I listed some items that were in my shop that I would NOT be working on and instead dispose of, I did not mention to large and obvious boxes since I am simply holding them for another museum to pick up. I have an IBM Z9 mainframe and an IBM 3490 tape system, plus a few small boxes related to them. 

Finally, I did a bit of work on the pin corrosion issue with the Altaid 8800 kit that I had assembled. By cleaning and repeated insertion/removal into the socket I was able to improve the connectivity enough to get the processor to operation successfully about three quarters of the time I reset it. It was still sensitive to movement. 

I had bought a second 8080 on eBay (from a source that was less likely to be a fake from Taiwan or China) but it looks like I won't need to swap that in. When I had a ten minute break from typewriters later, I managed to get this to become solid and reliable. I hooked up a terminal program and worked with the Altaid monitor and CPM.