manual paper tape reader

[Giovi Alex]

...if anybody would try to implement a paper tape for the Altair-duino, here's a interesting link: http://www.e-basteln.de/computing/papertape/overview/

[Walt Perko]

Hi, 

I'd love to build one to play with, but I'd rather somebody did a group purchase to build up kits with all the components and I just tagged on for one kit.  

[Giovi Alex]

is there any kit for a paper tape reader, like a teletype???

[Tom Lake]

There is but it needs a parallel port rather than a serial port:

http://jmprecision.co.uk/shopping/start.php?browse=1&cat=20&=SID

[Walt Perko]

Hi,  Looking at that kit in the UK it looks much larger and more expensive than the kit from Germany which uses a USB port on the PC.  Back in the day, the OP-80A kit came with a little blue project box like what we could get at Radio Shack ... about 3" long 1" tall and 2" wide.  It also had a clear plastic paper tape guide over the top so when the paper tape had folds or kinks, the plastic guide kept them smooth when pulling the tape through.  

I like the design of both of these paper tape readers, but at $100+ for the UK version ... it's too expensive to also have to convert from parallel to serial data for real use + figure out the software ... although I do have some scanned in paper tape reader programs from the "1975 Altair Software Library" posted on my website.  

[Tom Lake]

Do you have a link to the German unit? I couldn't find it in Google.

[Tom Lake]

Found it, thanks. I wouldn't call that a kit, though. You have to have the circuit board fabricated, and build the case from scratch.

On Tuesday, October 19, 2021 at 6:37:50 AM UTC-4 r4r...@gmail.com wrote:

[Chris Davis]

David created the parallel port card specifically to read from the OP-80A (or equivalent reproduction.)

[Giovi Alex]

I believe that the most interesting part of that: http://www.e-basteln.de/computing/papertape/overview/ is the idea; I guess (just guess; I didn't play with Arduino programming yet and I don't know for sure, actually) you would read the paper tape and transmit the result over the Arduino serial output. It would (?) be possible to connect it to the Altair-duino serial port. Maybe. Should be investigated...

[Chris Davis]

Wow, I really like that reader from Germany.  I think I'm going to play with that.

[Walt Perko]

Hi, 

I think we could get a group purchase going with BrianW. in Germany.  I'm hoping he jumps into the forum with his kit idea.  

I am also thinking that sans the Arduino module, this would just be an OP-80A ... but at less than half the price!  

[Thomas Niccum]

Now we just need a paper tape punch kit to match!

[Tom Wilson]

Yeah, the e-basteln model looks super interesting. It might be interesting to create some sort of pickup reel for the tapes, too... 

I haven't played with paper tape for a long time, but I remember testing the ASR33s back in my first 8080 assembly class. We used Intel SDK-85 machines  connected to the teletype, and I'd save my programs by using the memory view command and punching a tape. The SDK-85's monitor program was able to read text in the same format back in to memory, so saving and loading could happen to any device that connected to a serial port: paper tape, magnetic tape, or even the MK-1 Optical Transducer and Manual Digital Input device. 

Tom Wilson
wils...@gmail.com
(619)940-6311 

--
You received this message because you are subscribed to the Google Groups "Altair-Duino" group.
To unsubscribe from this group and stop receiving emails from it, send an email to altair-duino...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/altair-duino/7b102520-b5e3-481d-9d7b-5f604dc4d903n%40googlegroups.com.

[Walt Perko]

Hi, 

I can design 3D printable parts to build a reel to reel MCU controlled reader assembly and probably a separate paper tape punch device too.  

I'm figuring using a RoboGuts™ circuit board with a PIC chip programmed to step the tape one byte at a time.  Probably a $5 stepper motor to pull the tape through.  

I'm thinking that a set of servo motors might punch through paper tape.  I'd have to experiment to find the best motor and punch system.  Might need a set of steel PINs and steel Tubes for the process.  Hard to say, but a $5 servo motor flipping a 4" long arm might be enough leverage to punch holes in tape.  

First thing I need is some paper tape material to start testing.  

[Thomas Niccum]

I have a 3d printer so I can build along....

Paper tape - I see some on eBay... such as: https://www.ebay.com/itm/324807364065?hash=item4ba0070de1:g:NroAAOSwCRxhaz2w

You received this message because you are subscribed to a topic in the Google Groups "Altair-Duino" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/altair-duino/gTXT3jPUEQU/unsubscribe.
To unsubscribe from this group and all its topics, send an email to altair-duino...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/altair-duino/aaee75e1-0972-47cd-a0f1-822d30a42517n%40googlegroups.com.

[Roger Linhart]

Hi Walt.

I'm not intending to discourage you but I've read a few articles that mention the challenges of developing the paper tape punches for the old teletypes. Even the reader is a mechanical marvel. Might be worth looking into so you can avoid some of the pitfalls.

On Tue, Oct 19, 2021 at 3:16 PM Walt Perko <r4r...@gmail.com> wrote:

To view this discussion on the web visit https://groups.google.com/d/msgid/altair-duino/aaee75e1-0972-47cd-a0f1-822d30a42517n%40googlegroups.com.

--

Roger Linhart
Portland, OR  97230
Mobile: 541-690-8560

[Eric Smith]

On Tue, Oct 19, 2021 at 4:37 AM Walt Perko <r4r...@gmail.com> wrote:

Back in the day, the OP-80A kit came with a little blue project box like what we could get at Radio Shack ... about 3" long 1" tall and 2" wide.  It also had a clear plastic paper tape guide over the top so when the paper tape had folds or kinks, the plastic guide kept them smooth when pulling the tape through.

I've never seen an OP-80A like that.  Must have been early ones or something? All the ones I've seen came in a three-piece black anodized extruded aluminum case, with metal tape guides. I just took this picture of mine, made in 1977:

https://www.flickr.com/photos/_brouhaha_/51607866362/

[Giovi Alex]

I was wondering if is there any way to use a more common paper roll, like the ones used in table calculator with mechanical printer; even if it's quite a vintage stuff, they were used almost until today and the paper rolls should be easier to find and cheaper to buy... and, due to the bigger size, it should be possible to store two programs, one per side of the roll - or more bits in every row. Of course it must to be verified if the length is enough to store a program, I have no idea about that.

[Walt Perko]

Hi, 

I like the idea of using modern paper tape rolls ... they can easily be cut down to the correct width and the paper is thinner so punching holes would be much easier.  As a "vintage toy" the paper tape reader shouldn't care what kind of paper tape runs through it.  

[wgt...@gmail.com]

This evening I took my original OP-80A (pretty similar to the http://jmprecision.co.uk/shopping/start.php?browse=1&cat=20&=SID).

Jumpered a Arduino Pro-Micro 5V https://store-usa.arduino.cc/products/arduino-micro?selectedStore=us onto the OP-80A on to the Pro-Micro to it per the http://www.e-basteln.de/computing/papertape/overview/.

Dropped in the code into the Pro-Micro per http://www.e-basteln.de/file/papertape/Paper_Tape_Reader.ino.

Added serial code support to pin 1 and 2 at 9600 baud, 8,N,1 to the Pro-Micro via USB and the standard Arduino IDE.

Jumpered a RS232 to TTL convertor adapter https://www.banggood.com/RS232-to-TTL-Serial-Port-Converter-Module-DB9-Connector-MAX3232-Serial-Module-p-1487274.html?cur_warehouse=CN to the Pro-Micro, pins 1 and 2.

Little code on the Altair-Duino

Life is good

Thanks

Wally

Georgetown, TX

[John Kennedy]

Agreed - looks really nice! And it has a serial output that could work with AltairDuino (would it need software?). Maybe a good kit idea? :-) Hint

The trickiest part might be making paper tape, but it sounds like you could use a printer to  print strips that use black dots, and then cut and tape them together.

On Tuesday, October 19, 2021 at 11:48:20 AM UTC-7 famousd...@gmail.com wrote:

[Walt Perko]

Hi, 

Designing a reader feeder:  

Step 1:  getting the exact dimensions of the little device.  This is the first draft that I can tweak to the exact dimensions when I have them; 

The reader feeder will be easy to design ... Trying to make all the components 3D printable might be a little tricky for small printers, but I'm guessing the larger parts should also be able to be cut from plastic or wood.  I need this little reader mechanism design first to start figuring the rest of the auto-feeder design.  I'll work on the design over the next few days.  

[Brian Welland]

Hi fellow hobbyists,

No hint is required as I will have in early November a complete kit available for those that are still interested.

Currently I will have 3 sets available which would be made available on a first come – first served basis but if there is sufficent interest I could make a few more available but its the time required to get additional PCB’s ordered and received which would delay the dispatch of any more kits once these initial sets are gone!

The costs would be as follows:

(A) Set of 4 PCB boards (in Black) - phototransister, LED's, top and bottom mask apertures together with 4 light-tight spacers.

Price/set 10 Euro

(B) Set of electrical parts (inc connectors etc) as per the BOM (exc Ardiuno Pro Micro)

Price/set 25 Euro

(C) Generic Ardiuno Pro Micro (16Mhz/5V)

Price each 10 Euro

or

(D) A complete set of A, B and C as detailed above.

Price 40 Euro per complete set

You can choose one or more of these as appropriate to your specific requirements.

All the above do not include P & P but this should be no more about 10+ Euro and should all fit in a Jiffy bag but would depend largely on where you are and by which method etc.

Since I am based and living in France this will be nonimal within the EU (including the UK) but are prepared to dispatch internationally if you are prepared to accept the time and potential import costs which this may involve.

All payments would be via PayPal once an order has been accepted and confirmed but dispatch would be subject to when I have availability of the required PCB’s here in France.

Lets us all now all have the opportunity to remember and employ the “old methods” of operation of computers as it used to be and maybe how we can further appreciate in part how such basic things have changed in the mean time!

Brian

--

You received this message because you are subscribed to the Google Groups "Altair-Duino" group.
To unsubscribe from this group and stop receiving emails from it, send an email to altair-duino...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/altair-duino/a3cee3a4-0652-45f1-955a-c1e7e8cd0dean%40googlegroups.com.

[Thomas Niccum]

Hi Brian, would love to order one now!

[John Kennedy]

Sign me up, Brian! I'd love to give it a go.

On Wednesday, October 20, 2021 at 10:52:18 AM UTC-7 brwella...@gmail.com wrote:

[Giovi Alex]

Hi Brian, sign me up too, please!

[Giovi Alex]

Brian, can you post a link to the BOM?

[Walt Perko]

Hi,  The feeder design is down to five small 3D printable parts.  This design is with a stepper motor that can be triggered by the computer to step byte by byte or continuous motion.  The motor could be changed to a small hobby servo motor that just runs continuously too.  All the 3D printer parts fit within a 105mm space so almost all 3D printers can make these parts.  The tape hubs have a wide center hole that allows for less bending of the tapes for a smoother operation, but  although most programs shouldn't need to take too much tape length anyway, I can make those hubs hold much longer tapes.  The nice thing about this is since the hubs are 3D printed, you can just leave the tape on the hub for storage and protection.  Another 3D printable part could be a cover that encapsulates the entire hub with the tape on it for extra protection.  Using different color filaments you can color code for Utility programs, Game programs etc.  

The stepper motor in this design is a little slow, but if using a continuous rotating servo motor, then the machine could also do a fast rewind with a slight change of the hub caps.  

Trying to use a small hobby d.c. motor doesn't seem a good choice as the cost of a decent motor driver board just makes the whole thing cost so much more.  The stepper motor can be bought on eBay for about $5 and comes with a driver board.  Using a servo motor any MCU chip can control it by speed directly or just use a Maestro servo driver board (~$35).  

This is a fun little project.  The final design can be ready within a day or two of getting the paper tape reader assembled.  Then I'll know if I need to add tape guides to each side of the reader or not.  IF the machine needs tape guides, they can be 1/8"/3mm dowel rods sticking through mounts front to back.  

[Andy]

If I am not too late please sign me up!! 

cheers........... Andy

[Giovi Alex]

The 3D print reader sounds quite interesting, I can't wait for the first test :-)

I'm trying to imagine how to make a puncher; it would be more difficult than the reader... I was thinking about some different ways to punch the paper but i can't figure out a simple way for that; it seems to be some kind of  project for somebody with a good skill about mechanic and the proper tools.

[Walt Perko]

Hi, 

After exploring options to build a paper tape punch, it seems that a simple desktop vinyl cutter is probably the cheapest way to do it.  Most of these machines can cut very small fonts, hence they'll little round or square or rectangle holes.  An interesting part of this is that instead of using paper tape, the vinyl cutter could actually cut vinyl tapes.  The thickness of the vinyl might create a need to adjust the space for the tape to pass through the reader though.  

[pbi...@gmail.com]

Please add me to the back-order list Brian.  Merci beaucoup!

On Wednesday, October 20, 2021 at 1:52:18 PM UTC-4 brwella...@gmail.com wrote:

[Frank P.]

There's the small issue of source material in paper-tape format. My sole paper tape is circa 1973 FORTRAN source code for a text editor intended to be used on a CDC-1700. It's a roll of 8-channel oiled yellow paper tape (~1-inch wide):

Dealing with a roll this large required a tall trash can to collect the tape as it's being read and a hand-cranked re-roller. Later fan-fold tape came along and made handling a bit easier (if it folded when it was supposed to, otherwise you had a complete disaster on your hands :)

Did anyone happen to notice in the first post that the 8-channel (plus index/sprocket hole) reader was being used to read a 7-channel tape (with what appears to be only 6 channels punched)?

Regarding punching tape (thereby creating new source material), since the sprocket hole serves as a clock bit, it is punched smaller than the other holes. The sprocket hole is between bits 2 and 3 on 7- and 8-channel tape, but between bits 1 and 2 on 5-channel tape. Tom Lake has real ASR-33s and if their punches are functional they can make the real thing (8-channel as I recall). Quoting from the great World Wide Web:

The two most common widths were 11/16 inch (17.46 mm) for five bit codes, and 1 inch (25.4 mm) for tapes with six or more bits. Hole spacing was 0.1 inch (2.54 mm) in both directions. Data holes were 0.072 inches (1.83 mm) in diameter; feed holes were 0.046 inches (1.17 mm).

[Brian Welland]

Hi,

It was with interest the comments you made regarding the example of seeing a tape which appears to have no punching of the 8 bit column.

This not unusual as may be illustrated by the following examples

Here we have an example of a portion of a RIM tape typically as used to start an PDP-8 from an initial start where the core memory was completely empty or has been corrupted.

The format uses the least significant 6 columns 6-1 of consecutive frames of tape (characters) to represent 12-bit words which may be either an address or data.

Channel 8 if punched indicates that the current frame is leader or trailer and is to be ignored. This was typically all that was on the leader for about 12 inches or so.

Thus enable the user to feed the tape into a reader before starting the feeder itself.

If channel 7 is punched it indicates that this is the first of a frame pair which is to be interpreted as an address.
If channel 7 is not punched this indicates that the frame pair contains data which is to be stored at the address given by the previous address frame pair.

The Binary Loader {BIN} tape format used after loading if required after loading the RIM  tape is similar to RIM format but has the following features:




A punch in channel 8 only is leader/trailer code and is again ignored by the program.

Punches in both channel 7 and 8 indicate a field setting with field given by channels 6-4.
Like RIM, a channel 7 punch indicates that this frame pair is to be interpreted as an address.

If channel 7 is not punched this indicates that the frame pair contains data which is to be stored at the current address however, unlike RIM, the address pointer is then incremented allowing blocks of data to be loaded without intervening address pairs.

The whole tape is checksummed and the last 2 frames contain the checksum which is used by the Binary Loader as a coarse verification that the tape has been read correctly.

All the above assumes we are using a standard 8 bit format DEC tapes which are 1 inch width.

Should we have a paper tape  witch is punched in the 7 bit format the above still applies but in this case the 8 bit is now absent and the reader software will totally ignore it if you set the links 5BIT and TST are as specified.

In the case of a 5 bit punched tape this is or should be of 11/16 inch width and the tape spacers will or should thus be set accordingly. This naturally repositions the feeder holes into the correct position and the software thus adjusts to completely ignore the unused bit positions provided the  links 5BIT and TST are as specified.

Since it has been over 40 – 50  years since paper tape has been regurally used the availability is now   rather limited and the availabilitity of suitable punching equiptment is also now very expensive, often very unreliable and as a result often subject to high failure rates.

Dispite this there are still a few suppliers who will supply new punched 1 inch wide tapes suitable for our use (such as jmprecision.co.uk) and will punch them with your own bespoke programs provided that they are provided in the correct format.

Naturally as hobbyists we can use all types of alternative materials as experiments as it is assumed that it is not envisagived that the regular use of these types of readers would be employed for any  other commerical or other types of uses.

Just as a point of  interest we disposed over twenty years ago a whole box full of similar tapes into the waste bin after we started to use regularly all types of floppies and other forms of permanent program storage.

In hindsight this would appear to have been unfortunate but this is what has often happened to a lot of this type of stuff in this so-called technology advanced and now throw out  “modern age”.

Cheers

Brian

To view this discussion on the web visit https://groups.google.com/d/msgid/altair-duino/9df4dfb3-7b4e-4dae-a1ce-3f60fb8e3f9cn%40googlegroups.com.

[John Kennedy]

After building my tape reader (thanks for the kit!!) getting some tape was an issue. So I made some using a Cricut paper cutter. 

It was not a quick process, but it worked!

I am also thinking of using a small thermal printer which might be easier AND has the advantage of generating strips. Cutting them into the correct width will be the tricky part.

[Walt Perko]

Hi, 

I've been thinking that since vinyl cutters are so cheap, that might be the way to make paper tapes from cash register paper rolls.  The vinyl cutter can cut the holes and the paper to paper tape widths on the fly.  

I'm still waiting for my kit from France.  I hope it gets here soon.  

[John Kennedy]

What a vinyl cutter? Like a Cricut? A thermal printer would be worth trying too (the reader kit can read black dots on white, apparently - hope to try soon).

[Walt Perko]

Hi, 

Cash Register Paper Rolls are cheap, but too wide.  A vinyl cutter can cut the width down to two or three or maybe more of paper tape width  spools and cut the holes, or you could print the dots first, then just use the vinyl cutter to cut the paper into nice perfect strips.  

I've seen vinyl cutter videos showing micro size cuts in all sorts of materials that cost less than $150 ... I just don't see how to make a paper tape spool and a punch for less than $150.  

[steveukman]

There is a  useful Github site, if you Google "ptap2dxf" (I don't post links).  The author,  Steve Malikoff, provides instructions and supporting software to create paper tapes using a vinyl cutter.  It looks really great, and the documentation is really comprehensive.  It may require some splicing of tapes, but with roll-feed adapter capability becoming more common, I wonder if this limitation can also be overcome.

Of course, there is nothing quite like seeing (as well as hearing and feeling) the paper tape come out of a  punch machine for nostalgia.  I have seen a few "surplus" punches at reasonable prices, but most require driver electronics and produce 5 bit data.  Nothing that some electronics and firmware cannot solve!!!

[Walt Perko]

Hi, 

5-bit data is all capital letters, WWII Teletypes like the Model 17 or maybe even 19 and older.  

As for cutting cash register paper spools, I would think the vinyl cutter would just be sent the GCode for the length of the spool and cut the whole spool into paper tape widths.  

[Mark Moulding]

Regarding cutting cash register tape down, I've had good luck just using my radial-arm saw to slice the rolls.  The bandsaw would probably have worked too, but I have a really nice blade in the radial-arm, which leaves a very smooth surface so that the edges of the tape are smooth.  Naturally I use a jig to hold the roll - I started out with just a Jorgenson clamp, but now I include a couple of blocks with curved inner surfaces to grip the roll mor firmly.  With this arrangement I can get two paper tape rolls from a single roll of receipt paper.

~~
Mark Moulding

[Walt Perko]

Hi, 

Finally!  I got my paper tape reader kit today!  I got measurements figured out and now started 3D printing the first prototype reader machine.  

Now I need to buy some filament to print all the parts.  It shouldn't take too long to get a good working machine setup and tested.  

I'm going to test it with a $5 motor first, but I think it should easily work with a $15 motor.  The motor speed controller costs about $6 too.  The whole machine tape feeder system will run on a 6V d.c. wall-wart.  

[Walt Perko]

Hi, 

Got the prototype paper tape reader machine 3D printed; 

I have two FEETECH FS90R Micro Continuous Rotation Servo (!$5ea.) 

My 3D printer is small so I chopped the base in two parts to print, the bolts on the reader hold the assembly together just fine.  

The slots in the hubs is so pushing the end of the tape through both the spool and the axel the servo motor will pull the tape.  Using a cheap servo tester you can adjust the speed for best results reading in a tape.  

After the tape is read, then slide the spool off the axel to release the tape from the axel, then slide the hub back onto the axel and put the end into the other hub and axel to rewind the tape back onto the spool.  

The two wooden dowels are 1/8" diameter and can be glued into place so they don't drift or fall off, they just help guide the paper tape down to the level of the slot.  

My reader I added a 1mm thick spacer on top and bottom for better clearance of the LEDs and Photo Diodes, I also added 0.25mm thick spacers in the center to open the slot a little more and also guide the tape through the center.  

The whole machine is less than 200mm/~8inches wide, about 75mm/~3inches front to back and 80mm/~3inches tall.  

I used M3x35mm bolts to hold it all together and made two 18mm tall legs glued under the two sides of the machine to keep it steady.   

IF you 3D print a spool for each of your tapes, you can also print a spool cover (dust cover) to protect the tape.  

All the .STL files and photos etc. are in the attached .PaperTapeReader.zip file ready for 3D printing.  

I did tweak the design a little more after my prototype print so I fairly sure everything is going to be very nearly perfect.  IF you have a suggestion for a design change please forward it to me.  

[Mark Moulding]

Wow, Walt, that looks terrific - nice job!  Have you tested it with the reader yet?

[Mark Moulding]

What design tool do you use for your 3D designs?

[Walt Perko]

Hi, 

I haven't tested it reading a tape yet because I still haven't gotten everything setup and working with the I/O Expander set.  

[John Kennedy]

Very cool! I build the reader, but was thinking of a mechanism like this. Then I remembered: I don’t have any tapes :)

[Walt Perko]

Hi, 

IF you take the .STL files to your local library, they might 3D print the files for FREE.  That's one of the nice things about my local public libraries here in Las Vegas.  

The servo motors usually only cost about $5 each.  https://www.pololu.com/product/2820

You can find really cheap Servo Testers on eBay.com ... then just add a 6V battery pack and your machine is up 'n running.  

[John Kennedy]

I have the tech to build it, but no tapes!

[Walt Perko]

Hi, 

Maybe somebody with a paper tape reader/puncher (like an ASR33 Teletype) could make a bunch of tapes for us?  

I'd love to get something like CP/M 2.2 and BASIC on a couple of tapes, or a compiler (Pascal?), or maybe the best text editor that can run in CP/M5.  

I'd be happy to pay $5 for a pair of newly made tape(s) fan-folded into a flat envelope.  

[John Kennedy]

I found some original paper tape, and I will be seeing how well my Cricut can do with it.

What level of madness is this to try and recreate loading programs from tape? Are we insane? :-)

[Al Schemmer]

I have an ASR33, hasn’t been out of it’s corner for 30 years, if enough interest, I could dig it out and see if I could make it punch some tapes for peoples.

 

On Sunday, October 24, 2021 at 10:46:12 AM UTC-7 brwella...@gmail.com wrote:

Hi,

It was with interest the comments you made regarding the example of seeing a tape which appears to have no punching of the 8 bit column.

This not unusual as may be illustrated by the following examples

 

Here we have an example of a portion of a RIM tape typically as used to start an PDP-8 from an initial start where the core memory was completely empty or has been corrupted.

The format uses the least significant 6 columns 6-1 of consecutive frames of tape (characters) to represent 12-bit words which may be either an address or data.

Channel 8 if punched indicates that the current frame is leader or trailer and is to be ignored. This was typically all that was on the leader for about 12 inches or so.

Thus enable the user to feed the tape into a reader before starting the feeder itself.

If channel 7 is punched it indicates that this is the first of a frame pair which is to be interpreted as an address.
If channel 7 is not punched this indicates that the frame pair contains data which is to be stored at the address given by the previous address frame pair.

The Binary Loader {BIN} tape format used after loading if required after loading the RIM  tape is similar to RIM format but has the following features:

A punch in channel 8 only is leader/trailer code and is again ignored by the program.

Punches in both channel 7 and 8 indicate a field setting with field given by channels 6-4.
Like RIM, a channel 7 punch indicates that this frame pair is to be interpreted as an address.

If channel 7 is not punched this indicates that the frame pair contains data which is to be stored at the current address however, unlike RIM, the address pointer is then incremented allowing blocks of data to be loaded without intervening address pairs.

The whole tape is checksummed and the last 2 frames contain the checksum which is used by the Binary Loader as a coarse verification that the tape has been read correctly.

All the above assumes we are using a standard 8 bit format DEC tapes which are 1 inch width.

Should we have a paper tape  witch is punched in the 7 bit format the above still applies but in this case the 8 bit is now absent and the reader software will totally ignore it if you set the links 5BIT and TST are as specified.

In the case of a 5 bit punched tape this is or should be of 11/16 inch width and the tape spacers will or should thus be set accordingly. This naturally repositions the feeder holes into the correct position and the software thus adjusts to completely ignore the unused bit positions provided the  links 5BIT and TST are as specified.

Since it has been over 40 – 50  years since paper tape has been regurally used the availability is now   rather limited and the availabilitity of suitable punching equiptment is also now very expensive, often very unreliable and as a result often subject to high failure rates.

Dispite this there are still a few suppliers who will supply new punched 1 inch wide tapes suitable for our use (such as jmprecision.co.uk) and will punch them with your own bespoke programs provided that they are provided in the correct format.

Naturally as hobbyists we can use all types of alternative materials as experiments as it is assumed that it is not envisagived that the regular use of these types of readers would be employed for any  other commerical or other types of uses.

Just as a point of  interest we disposed over twenty years ago a whole box full of similar tapes into the waste bin after we started to use regularly all types of floppies and other forms of permanent program storage.

In hindsight this would appear to have been unfortunate but this is what has often happened to a lot of this type of stuff in this so-called technology advanced and now throw out  “modern age”.

Cheers

Brian

 

On Fri, Oct 22, 2021 at 5:10 PM Frank P. <fcpr...@gmail.com> wrote:

There's the small issue of source material in paper-tape format. My sole paper tape is circa 1973 FORTRAN source code for a text editor intended to be used on a CDC-1700. It's a roll of 8-channel oiled yellow paper tape (~1-inch wide):

To view this discussion on the web visit https://groups.google.com/d/msgid/altair-duino/3e306e87-a5e7-4cc0-9fd7-86f7cc821bb3n%40googlegroups.com.

 

[Chris Davis]

Al, if you're ever interested in selling that, I'm within driving distance! :)

[Walt Perko]

Hi, 

Has anybody gotten their I/O Expansion parallel port to read in a paper tape yet?  

I hope to give mine a try soon.