IBM 3420 9-track tape drives arrrive for restoration. 800 lbs each!

I might have fallen into the deep end. It started with the IBM 360 control panel ( • IBM System/360 Front P... ). Now I am adding some rather heavy bits to complete the system.

[@kuzadupa185]

I can just imagine how excited you were when that delivery truck arrived with these incredible units

[@MS-196x]

I worked on these in the late 80s, spent many an hour replacing faulty vacumn switches, adjusting read head amplitudes, replacing fibre optic bulbs in the "horse shoe " as a slightly dimmed bulb could cause all sorts of issues! And even back in the late 80s the vac/pressure tubes had become hardened so we alway carried spares. The capstan wheel was a very delicate part and needed real care when working on. The white paper tape near the head is part of the auto cleaner assy. We still had customers using these into the 90s 🙂 They were marvels of engineering and it was always impressive to see a well adjusted unit with the tape working within the limits of the collumns to allow the tape to be moved without too much tension backwards and forwards by the capstain at high speed.Hopefuly you'll be able to find some MAPs and MIMs to help with the rebuild 🤞

[@osiris1802]

So many dear memories. That was the golden age of computers. Mainframes are the best and I miss every single hour working with them.

[@buzzcorey9054]

I am IBM retired and as a Customer Engineer (CE) I worked on these units. The customer account I was assigned to originally had twenty four model 2401 tape units on three different 360 systems. They required a lot of maintenance. The account finally upgraded to the 2420 model and life for me became much easier. They were amazing tape units, very reliable. Just make sure you do not poke you finger through the fragile capstan (the part that moves the tape). Doubt you can find a replacement anywhere now. The address 381 on the front upper panel is the address of the drive (channel 3, unit 81).

[@rty1955]

Buzz Corey the 2401s had an amazing rewind time! I also remember the head assembly was made in france as well. We had one srive where the heads became magnetized and a tape sort would always fail on this drive. The CE came in and ajusted the read amplifier he kept wondering why the read signal kept dropping. He kept adjusting the amplifier. After obtaining a new head, I suggested to degauss the old heads as i have aeen this before in video recording. He grumbled a little bit and obtained a degauser and wiped them iver the heads. Bingo! Problem went away!

[@joefranks4235]

Well, they were not very reliable where I worked with these drives. Man, they were a pain.

[@eugeneharry481]

@@joefranks4235 There were problems in the beginning, mostly circuit board failures, but after that was cured, they were very reliable.

[@crazyedo9979]

Hello from Germany. Maybe you are so generous to answer may question if it is possible to run such kind of tape unit as a "stand alone device" in some kind of "test mode" so that it can load and unload a tape. Background is that there is a single 3420 unit in our computer museum and it would be a really eyecatcher if it can operate a little bit.😁

[@cnvogel]

Marc, you are a crazy person, but in a good way! I'm really looking forward to your videos documenting the repair of these machines.

[@vxolimpic84]

How excellent! I am an old timer who watched this equipment running. I love watching you work on these old machines. I can't wait for some videos of your journey to repair these units. It will be a real challenge to make sure all the different vacuum pressures and air pump pressures mesh for perfect functionality. I've always suspected that there would be glitches related to oxidation of some or all of the tiny jumper wires on these old boards, changing the resistances all across the board. Keep up the great videos and thank you for everything.

[@stephensejda5213]

Like seeing an old friend. Still have my test box used for offline fixes. Thanks for posting!

[@jerry3890]

The 2420 mod 7 came out in 1968 I believe. It had a huge cage of electronics and was very poorly laid out. A low cost 2420 mod 5 was released in 1969 which used MST for electronics, and had the much nicer layout used later in the 3420. Most 2420 model 5's were converted to 3420s. If you have a converted 2420 it will have a serial number starting with "9" (9xxxx). If you can get the service manual for the 3420 it sometimes splits into different sections for 90000 series machines. The 3420 was one of the first machines to use MAPs for troubleshooting (Maintenance Analysis Procedures). If you need help on that I've fixed about 843,297 of them.

[@gregames897]

The 3420s and their 3803 controller are 370 generation which I spend a bit of time maintaining in the '70s. IBM 2xxx perepherals are 360 era, 3xxx are 370 era. Keep up the good work!

[@pilgrimm23]

Man.... I worked with EXACTLY THAT MODEL on an IBM 360/65 OS360/NIH HASP; Dual SPOOL, Dual DASD system.. we ran years... 1970s..ago.. in New Mexico... You made me happy.

[@hiteck007]

What did that system do exactly????

[@Spikejwh1]

Aaahh, Memory lane... I used to be an IBM specialist on these tape units Spend many hours repairing and adjusting them. You probably figured it out already but the idler that was lying around goes on the air pump assembly to tighten the flat belt. It is a pity but about 2-3 month ago I threw away a whole suitcase full of spare parts for these units. Vacuum Switches, Light pipes, lights, idles, tubes... my personal spare parts magazine I used at the time. BTW there are supposed to be more books. They are called ALD's and MAP's. You need the MAP's for the adjustment procedures for Capstan tacho and R/W Heads. Be advised that the Device interface cable between Tape unit (3420) and Control unit (3803) are different than between Control Unit and CPU (Channel) They are not interchangeable !

[@gmale2624]

Thanks for the trip down memory lane. My first job after graduating from college was working on the IBM 360/370 systems and all of the peripherals as a field engineer. Good luck restoring those tape drives.

[@ksbs2036]

Marc, I rewatch this video every year. It brings a smile to my face. I truly enjoy your squad's exploits. I expect you are two or more years behind due to the amazing AGC restoration

[@LMacNeill]

Whoa!! The these things are *so* complicated!! I had no idea tape drives could be so complex!! And a *giant* controller box to go with them?! *Seriously* complicated!

[@RaymondHng]

50-to-250 megabytes of tape storage in one of those drives. You will need 512 of them to equal the storage of a 128 gigabyte USB drive the size of a pinkie finger.

[@haweater1555]

Today, the data capacity of a room full of these beasts fits in a solid state chip balanced on the tip of your finger.

[@iluvsweaterpuppets9166]

That is a thing of beauty, I’m just discovering about machines and systems like this and I want to thank you for taking on a project like this. 👍🏾😎

[@MaxKoschuh]

woooohoooo, this is so crazy !!! Absolutely amazing. And the TCU is just wonderful.

[@johnmoreton459]

Nice to see those tape drives and controller. I didn’t work on those drives, did work on 3411 and about 10 different systems 360/20, Sys 3, System 34, 36, Series 1, System 7, AS 400. All of the attached i/o devices, was a teacher for 1403. You can’t convert your power from 2 phase 208/230 to 3 phase 208/230. Your house current would have to go to 400 amps to handle this equipment. Those are Russle Stowe connectors 3 phase + ground 60 amp connectors. You need bus and tag cables to hook up the tape drives the controller. System 370 uses a voltage conversion system and most are water cooled. 400 hertz converter, with cables that look like anaconda snakes. If you are making a static display great to make a functional system requires an electrician and power requirements that most non commercial building or homes do not have nor would your local government allow. I worked in New York city. I had Equitable Life ins as a customer and multiple other customers I was an Account Customer Engineer. Was a great time to work.

[@joefranks4235]

Oh my gosh! I remember working with this tape drive when I worked at Viskase Corporation in Bedford Park, Illinois. I hated when those things would loose the vacuum. Our job would blow-up. Also, the metal EOF marker on the tape would sometimes bypass the sensor and the tape would come off the spool onto the collection spool. I was able to get the tape back onto the normal reel, but you had to know how to trick the machine. Boy, I still have nightmares about those drives after all these years.

[@ezragonzalez8936]

If I had those in my garage I would had taken them to a dump site this is of course before I knew how much old equipment means to so many people .. I have to confess 12 years ago I tossed in the garbage a garage full of vintage commercial equipment including some late 60s IBM stuff HP Texas Instruments computers .. which I had no use for and even attempted taken them to salvation army thrift stores they declined saying they were oversize and obsolete .... believe me I still cant forgive myself!.. thank you Marc for sharing your passion with us!

[@chrisbragdon5901]

I have funny, mixed feeling about attempting to put together a legacy IBM mainframe system as, to me, it reflects no real fond memory except the many folks I ran into dealing with these things from day, to day. Running around town fixing these things 24/7 got old as assigned account CE’s failed to pull their weight and let things go, so I had to go out and put out the fires. All. The. Time. To me, the real troopers that made this mad system work were the grunts that sacrificed more than you can possibly imagine. ... But then again, I’d love to frezbie an errant 1052 console printer through a clean, intact window. You know, just for grins!!

[@johnkoski4338]

I worked on the design of that tape drive at IBM in 1968/69. The first circuit board design of my career is in your video, a -4 volt series regulator for the logic system. The regulator is an SMS board at lower front left.

[@CuriousMarc]

Awesome. Would be nice to get in touch with you! You can contact me through my About... channel page: kzbin.infoabout

[@bertoid]

That's a fantastic score you have there. I'm amazed such stuff is still to be found. But I'm sure that this gear is from the System/370 era - the standard tape unit for System/360 was the 2401.

[@CuriousMarc]

Yes, you are right, Iggy also just reminded me that these tapes and this controller were introduced with the 370. This particular model 6 can go up to 6250 cpi. The equivalent tape for the System/360 was the 2420, Phase Encoded, would go to 1600 cpi, and was announced in 1968. It looks identical, but the electronics use first generation SLTs. The 3420 was announced in 1970. My 360 panel is from 1969, so I think I hooking the two together is still historically legit ;-)

[@Spikejwh1]

Memories... Used to repair them as an IBM CE.

[@chewbaccasaurusrex692]

great videos I'm glad to see people saving these.

[@haweater1555]

3:30 All those tubes and flex hoses remind me of the house mechanical systems seen in the "Brazil" movie from 1985.

[@MrNeptunebob]

Those hoses look like what you find in central vacuum cleaner systems.

[@johnopalko5223]

This brings back so many memories. I really miss working on the old mainframes. I loved the smell of the machine rooms. The combination of the 68-degree F. chilled air and the running equipment was a unique aroma that you just can't find any more.

[@chrfit1]

Your dedication is inspiring :)

[@lavaq9593]

It's interesting that in the 1980's Los Angeles had an IBM System 3090 installation using STC {Storage Tech. Co.} tape drives! They became obsolete, the shop converted to tape cassettes on an automated system. These days, they're probably all gone. I didn't realize the weight of these devices! LOL! Thanks for the video!

[@lanz1987]

Really psyched to follow this project!

[@msylvain59]

It happened to be also, hunting for a collectible item so hard to get and rare, that I finally end up with several units of the same thing.

[@JPennDotCom]

Nice acquisition, thanks for sharing.

[@uniservo]

Excellent. I think I know where those drives came from, and it is good they are finally in safe hands. 3420s dried up in the wild about ten years ago. Hopefully soon I will be getting a string of them imported for a friend (I have plenty myself). One thing to note - while the steady state power draw is not all that horrible, those tape can create very large current surges when the motors start and stop.

[@CuriousMarc]

+uniservo: yes, I think you know. I need to pay you a little visit to see your collection when I am on the East Coast... Did you get yours to work?

[@TCGProductions03]

Do the motors backfeed the AC line when they stop?

[@tickertape1]

I would imagine there is protection for that

[@Mossy-Rock]

Wow!!! Congratulations! This was my favorite IBM tape drive of all time. You now have a complete subsystem so theoretically these drives will be able to read and write real data to/from an external system via FPGA that you mentioned, although successfully interfacing an FPGA to bus and tag channel architecture will be challenging. One thing - I always thought that the IBM 34xx series of tape drives were officially considered to be of the IBM 370 family, not the IBM 360 family (although they could easily be used on IBM 360). The tape drives of the IBM 360 family were the IBM 24xx series.

[@PhilUKNet]

Definitely System/370. Central London computer centres I worked in based around 3081/3084/3090 had huge rooms full of 3420's.

[@johnlister]

@@PhilUKNet Plus all those tapes that went back and forth to BACS…

[@nealelliott]

very cool! that's a very different way to use mercury switches, instead of using them for old thermostats. I still have a bunch of those switches at home, and I don't have a creative way to use them.

[@BilalHeuser1]

It's good to see that you have such an understanding wife ... :-)

[@Veso266]

how you know that the lady on the beginning is his wife?

[@stuartmartin3408]

Veso266 the caption “ Wife” for the translation kinda gave it away.

[@Veso266]

oh yea no just a question how did you get a french wife in America?that's like 2 lucks in one, first you get a nice understanding lady as your wife, then you can even speak your native language with her

[@evhvariac2]

His wife is thinking “oh no another piece of nostalgia!” Lol. It’s great though

[@TymexComputing]

well i must say that at 1:09 the lady looks just like regular wife when you bring home something just for fun :)

[@AaronJackson1]

Looking forward to following this project! :D

[@veepedaldude9404]

Your videos are relaxing.

[@TecKonstantin]

Just AMAZING, i cant wait so see all of this, it is sad to see such pieces of history die and the knowledge of it! You and your friends are the real heroes!

[@robertfallows1054]

We had a Tandem Nonstop with 2 vacuum column drives. I don’t know who made them. Our team was not fully trained on how to maintain and fix them so that could have been a part of the problem. They were somewhat unreliable. Full backups might take up to 11 tapes and it was a nail biter to see if it would make it through that many tapes. Nice to see videos of that old equipment but not so fun on a day to day routine

[@brucelemken3249]

The fiber optics are for both the capstan motor encoder as well as the rewind encoders on the tape path. It appears to be a model 8 if I remember right they had the autocleaner which is the black plastic lookin box on the bottom

[@johnlister]

Those were the great days of tape. Where you could actually see the tape moving in little jerks as the tape was read in blocks. (Which makes those of us who know laugh at all the 70s and 80s movies & TV where the tape drives just spun continuously). I have believed for a long time that any technology, as soon as it is perfected, is obsolete. Think CDs, DVDs… And the 3420 was definitely the apotheosis of 9-track tape drives. They were so easy, but I forget the exact buttons. Window down, slap on the autoloader cartridge, then press load et voilà! Stand and watch the drive unlock the cartridge and unload the tape. My memory is faulty - I dunno why I remember the full spool being loaded on the left which is clearly wrong. But wasn’t there an (aftermarket?) display on the top of the drive that would alert the operator when manual intervention was needed - Mount Tape #XXXXXX, Unload, etc?

[@dalebrowne6229]

Before I left my work in a banking envoroment back office back in 2009, they still had 5 of these units due to clients not evolving their structure. We also had 4 of the tape cart. systems. I still have a bottle of the cleaning solution, 99.99% alcohol

[@shyleshsrinivasan5092]

Sir, I don't think that Mercury switch is for sensing Air Flow. Its most probably a switch to detect if the System Cabinet Door is Open or Closed. Great video ! Thanks a lot for this Sir !

[@itskevinjustkevin]

can't wait to see this in action

[@missyd0g2]

I remember helping install the buss and tag cables. Making the bends to bring them up from the floor and attaching them. If you were short on the cable length you were screwed. I enjoyed the 370 and the 3705 FEP for SNA networking. Best of luck.

[@johnlister]

Installing Bus & Tag cables was a pain. Or removing them. You had to (un)weave the cables from all the other ones under the raised floor while taking care not to damage the rather bulky connectors. I know why some people just snipped off the connectors and pulled hard! Marc would have loved a 3705. I think it was one of the last IBM devices with real core memory. And don’t get me started on SNA, IBM’s great networking failure.

[@PlayerOneStart]

1:20 Happens to me EVERYTIME! (Has two sides to choose from to open, chooses wrong side....) :) Good video, learned about about these machines.

[@CuriousMarc]

+Player One Start: Oh, good, I thought it was just me!

[@bzert281]

you're recreating my first computer room! all you need now is a 3203 printer, a card reader, a keypunch machine, a few 3350 disk drives and a 4381 CPU. Oh I guess a 3270 controller and some terminals. -then i can be 19 again. ;)

[@johnlister]

Ah, yes, the IBM 3350. I have to laugh at the fact that we were impressed that they could store ~320 MB each at some fantastically large price. And I have more online disk storage in my apartment than ran a large UK bank in the late 1970s!! We had the ones with the fixed heads. I see in the Wikipedia article about them (en.wikipedia.org/wiki/History_of_IBM_magnetic_disk_drives#IBM_3350) that the fixed heads were used for JES2 spool checkpoints and swap spaces. Nah. The canny systems programmers used them for the directories of system library PDSs (with some very clever dataset allocations) so that loading a program from the system libraries was faster.

[@peten6445]

Marc, This looks like the old JPL first IBMs with punch cards..

[@Noodleude]

beautiful!

[@jonathanvanier]

Marc, any plans to assemble a small working System/360 system? That be a great follow-up on the Apollo AGC series! In any case, love your videos! P.S. I can also take a Burroughs Large System or a UNIVAC from the 60s/70s ;-)

[@1912RamblerFan01]

12:12... It just needed some friends. ;-) Great project - it would be great to see a System/360 restored to mostly "operational" condition (even if it means running the processing side of things via Hercules)

[@NSResponder]

Fun fact: Ampex got into the audio tape business by taking 9-track tape stock that didn't pass QA for data use, slitting it to 1/4", and selling it to recording studios. Analog recording was a lot more forgiving.

[@chrisbragdon5901]

All 3420’s toward the end of their lifespan’s exhibited disintegrating vinyl hoses, foam rubber insulators, rubber door seals and became a PM nightmare. The magnetic tape also became an issue, especially with 3420-8 tape drives as the tape substrate holding the data holding iron oxide surface also disintegrated in the same fashion and as it moved at mod 8 speeds it would over heat and stick to the read/write heads, ruining the tape. And also ruining the tape drive itself. Lots of tapes from overseas caused so much grief it really spelled the end of 9 track tape drive subsystems. Mod 6’s can also be effected by this but to a lesser degree as they moved the tape slower speed over the read/write heads, causing less heat buildup. Spent time with many trips to the hardware store seeking many sizes of tubing stocking up on those midnight calls! beep beep beep beep!!! Oddly, the 2400 series tape drives didn’t suffer this problem, they had “Prolay” and tape motion issues.

[@natsteele5065]

You are completely crazy. I cannot wait to see what happens next though! If you're going to have the tape machines and controller, would it be out of the question to track down a CPU as well and have a real System 360 running in your garage?

[@CuriousMarc]

The 360/50 CPU, if we could ever find one, is huge. Then I'd have to fight against Paul Allen and the Living Computer Museum, I'm not gonna win... Not to mention the 10's of kW of power I'd need. So that is not completely impossible, but really far fetched.

[@525Lines]

They scraped them for the gold content, the same as they did with the core memory.

[@mrnemo204]

CuriousMarc Connect it to windows 7 or 10

[@525Lines]

I'm not sure an external 5.25 diskette drive is recognized by Windows. I'd like to see this drive be connected to it. I wonder if there's a new tape drive that modern PCs can see ...

[@RaymondHng]

It really depends on whether the BIOS on the motherboard supports it. The 5.25" diskette drive was not recognizable by my newer PCs, but it was recognizable by an older one.

[@vanceray1117]

Very cool. I worked on literally 1000's of those as a FE/CE for IBM in Dallas back in the early 80's! Actually - check the CE logs, I might have worked on these! :)

[@willharry6791]

Same here, I had the Sears account at their warehouse on S. Lamar St. in Dallas. The 2400;s were eventually replaced with Telex drives. Sears soon found out that the Telex drives were even more trouble prone than the 2400's, so they were replaced with the 3420's. There were four systems with eight drives each. No more pro-lays to adjust.

[@Belano1911]

I used to make the tag and bus cable pairs for these machines.

[@johnlister]

I’m sure it built strong arms!!

[@laapulsford]

The foam disintegrates because of ozone which is formed in most computer halls - the ozone negatively affects the foam.

[@actarus74fleed]

Stupendi

[@160rpm]

Looks like a pinball machine behind the top panel there lol

[@StampStories]

Sheiβe, that's amazing...

[@the_jcbone]

that's a Greek β (beta). The sz ligature look like this: ß. As in Scheiße. :-) But points for the effort!

[@Turambar3791]

Since I think that I am not the first one in saying it, you should listen to us, just burn one of those front of the others and say "If you don't work you will be burn" I bet that all of them will start working nicely, (except the one that you burnt) ^^

[@kuzadupa185]

I guess these drives measured how much storage space they offered per 100 lbs!

[@voidedspace5510]

I saw an eBay listing for these!!!!!

[@skynetcybersystem3tech]

👍👍

[@joseschuh4182]

Um sistema completo. S/370 145 com discos 3330 e TCU 3745 com NCP controlando linhas e terminais remotos. Sistema operacional VM acima de DOS ou OS. Linguagens usadas: Assembler ou COBOL ou COBOl/CiCS. Era o mundo da informática de então. O mundo mudou mas o mainframe IBM continua processando as transações do mundo.

[@bborkzilla]

IBM == I Bring Manuals!

[@douro20]

I Buy Monthy (system software packages typically run on a monthy licence plan)

[@willharry6791]

@@douro20 I've Been Moved

[@sneedsfeedseed3250]

How exactly did you manage to come across these IBM tape units?

[@38911bytefree]

What a magnificent gear. Cant understand why IBM contructed the board the way they did and not using routed PCBs with coppre traces. Some card are %100 hardwired, pain to trace a missconection. Sure this didnt happened very often because IBM quality was top notch and this GEAR was serviced regularly.

[@CuriousMarc]

I think this one is partially PCB traces and partially wires. I'd guess it's historical, and these are machine made. They had very advanced computer automated backplane wiring technology as early as the 1950's. The 1959 IBM 1401 is computer wire-wrapped. I'd also suspect it allowed flexibilty to do field modifications and install add-ons, something IBM had also been doing for a long time.

[@rty1955]

3420 tapes drives were never used on a 360. It was a 2400 or 2401 tape drives. 3420 was on the 370 models

[@CuriousMarc]

You are correct, they are from next 370 generation, as is the 3808 controller. But that's the closest I could get. You cannot get too picky when you find these... And it should work connected to a 360 channel (hopefully).

[@willharry6791]

Yes they were. They were 360 compatible. I was an IBM CE and I had 32 3420's at my customer account, all running on system 360.

[@chrisbragdon5901]

Mod 6, God it has the piggy back POS power supply!

[@jetraid]

I think is better to ask the electric company to bring you 3 phases than try to convert your home instalation. I wnat to see that machines working agian.

[@hollytimlick9470]

I want one! 😁

[@MikeHarpe]

How are you going to deal with the power? Those things gulped power. Can't wait to see it run!

[@johnlister]

Was the 3420 on the 440 Hz power also?

[@geoffcrisp7225]

I would like to know once you get it up and running what are you going to connect the bus and tags to??? Don't touch the capstan except with tape cleaner.

[@lawrencedoliveiro9104]

Note, people, how the controller circuitry (which handles all the actual I/O with the CPU) is in an entire separate cabinet. The concept of “Integrated Drive Electronics” lay a couple of decades in the future...

[@johnlister]

Wasn’t there a “string controller” or control unit that then talked to the channel (again a separate box in the /370 days)? And do you know why there were so many bus & tag connectors in the back of the tape control unit? Could it run multiple strings if connected to a block multiplexor channel?

[@Wizardofgosz]

So where are you on this project? Any progress? Also, with that SpaceX guy who's been helping you with the AGC restoration, you should be able to get the FPGA 360 emulator working no problem.

[@coryinthehouse5250]

Hey marc, any updates on what's happening with these? i love old IBM machines and would love to have a Alto style series of videos showing these being restored. great content keep it up.

[@CuriousMarc]

Still in the garage. I have gotten more pieces of the puzzle though: finally figured out what the weird power connector is and got cables and connectors, I have Bus and Tag cables, a tape tester. I should get a tester for the controller in the next few weeks. Most important, I acquired a 3 phase inverter that might barely have enough power to get one of these up. Stripped all the bad foam out, which was a big job. We think we have located a place that has the only 360/50 documentation we know of, but have not been able to digitize it (it's overseas). The IBM 360/50 is by far the longest term project I have, truly my "retirement project". We make progress little by little. But we keep being distracted by space hardware comes along and that we have to jump on.

[@ChickenBG7]

360 tape drives

[@tomkuhn]

Where did you find these tape drives? and where could someone get more?

[@lucaviggiani2189]

Are these the ones that had the rubber strip seal at the top? If you pinched the rubber, the door would open. A safety device in case you got your hand, head or other body part trapped while the door was closing. I remember someone also told me that the head cleaner for these turned out to be carcinogenic. MEK?

[@CuriousMarc]

Thanks, I didn't know!

[@rty1955]

Luca Viggiani yes. The 3420 models had a rubbee strip at the top of the door inside the metal frame to drop the glass front in the even of an obstirction and to abort the load sequence. The 2401 had a metal strip at the top of the door that did the same thing

[@SUNNETCTS]

Keep Update..

[@clemstevenson]

Where's the micro SD slot :-) Things have changed a lot since those days :-)

[@ReneSchickbauer]

"Portable mass storage? No problem. Just watch your step while we bring in the forklift truck..."

[@rty1955]

I am looking for a 360/30 front panel

[@Jorzef2]

Hello love your videos, did you work already on this beast?

[@CuriousMarc]

No, not yet. It will be a while before I can get to it.

[@Trev0r98]

These tape drives were from the System/370 - 3033 - 3083 era, yes? Not so much System/360.

[@rty1955]

Corrext the 360 era was 2401s

[@willharry6791]

@@rty1955 3420's also were used on the 360 series. Completely compatible.

[@flugschulerfluglehrer7139]

We are desperately waiting for the follow up.

[@jayherde0]

Interesting!! In my attic, I just found a couple of IBM360 type manuals that are about to find their way to the dump. Probably just error codes and messages, but IF you might be interested ...? I think we had a 360/370 in the early 80s with, I think, 7 of those tape drives. When they moved it out, I wanted to be the one to flip the main switch on the CPU that doesn't UN-switch ;-)

[@CuriousMarc]

Thanks, I'm interested. Send me a private message (go to my channel page, about tab, send message button).

[@rty1955]

Jay Herde that was the emergency power pull switch. Never pull that unless someone is getting injured! Someone pulled that at out installation and it cause many hours or repair to the CPU. it is best to request a cycled power off from the console. The CPU will send sigbals to the peripherals to shut down in Sequenxe as to not cause a huge power spike! I had to power down a very large 370 system and to watch it power down was awesome

[@tomlewitt]

@@rty1955 What happened to these huge systems if there was a sudden power failure to the building? Did they require powerful UPS setups for backup?

[@rty1955]

@@tomlewitt funny u should ask. I was working at a Bank facility at a 40,000 sq foot facility with vendors from IBM, CDC, HP, DATA GENERAL, and others. We had two IBM mainframes w/16 tape drives, sea of disk drives. We had a 625 sq foot UPS room. This room was full of bus batteries and a TRUE UPS (NOT a standby supply like most "UPS" systems) in other words the entire data center was always on the UPS even the A/C units on the raised floor. One afternoon there was a car accident and the car g it the pole with the Transformer on it. The entire building went dark. People kept calling the data center to see if we were still up & running, which of course we were. I came out of the Data Center to find out WHY the generator didnt kick on. Turned out the car knocked out 2 phases of power not 3. The generator did not start up because of this a d they called the electrician to get the generator to run. I informed them we had 45 min to live on the UPS before we HAD to power down in am orderly fashion or face certain hardware damage. The electrician got the generator running with 10 min to spare. A mainframe can take up to an hour to come up from a cold start.

[@tomlewitt]

@@rty1955 Wow that's fascinating. That UPS system must have been massive. And probably a tech's major nightmare, wondering if it will hold up, and the generator will indeed start! And in those days the batteries would have had to be continuously maintained, re distilled water etc... The biggest 'UPS' I've seen was in a large telephone exchange here in NZ, around 1971. It simply had a wall of car batteries, and possibly no inverter as all the relay stuff was DC anyway?

[@flugschulerfluglehrer7139]

Of course he speaks Mandarin... 👍🏻

[@525Lines]

Since the US government likes to keep old computer gear going for a long time, are there any companies offering service parts for these machines?

[@ariscop]

Probably not? ibm rented machines and were forward compatible since the 360, they're probably still running s/360 code but on modern system z mainframes

[@CuriousMarc]

Not that I know of, but they apparently still run old IBM 370 programs on emulated machines and attach modern web front ends to it!

[@CuriousMarc]

+ariscop: I believe you are right, the /z machines still support 360/370 code (!).

[@525Lines]

That stuff was so heavy, I'd bet a lot of it is in university basements. Not worth hauling up to trash. Probably covered in boxes by now.

[@CuriousMarc]

The problem is that these machines were mostly rented, not purchased outright. IBM would get them back at the end of the lease, and would destroy them so they would not compete against newer machines. So most of them have disappeared. Then of course they take a lot of space, so people got rid of the few that were left. And of the few that were still left, movers cut the cables, which renders them close to unrestorable. Let's hope they missed a few...

[@brucelemken3249]

The cards in the logic gate are SLT cards not SMS

[@lucasimark7992]

Was there ever a follow up to this video?

[@jix177]

Great machine - that's a lot of dust inside, did you find it down a coal mine?!

[@CuriousMarc]

It's mostly coming from the /;(/$&!! foam.

[@ScottDotDot]

I was thinking how antiquated a concept to rent computer equipment by the hour.... oh wait, my ec2 instances disagree. 😭

[@telegraphhill803]

Do you need the original 3420 Tape tester? I have one in my Garage. Is is a small device you need to test your 3420 mechanically.

[@CuriousMarc]

We will indeed need one. Carl has lent me his, but we don't know if it works. We might reach out to you if it does not. What else do you have in your garage ;-) ?

[@idahofur]

Did you do anything with the tape drives? Just wondering. I'm more interesting in you getting back to the hp2000 minicomputer and such. :)

[@CuriousMarc]

Just preparation work so far. Cleaned up the crumbling insulation. Got the power connectors (these were very hard to identify and even harder to find) and the Bus and Tag cables. Got an IBM tape tester and restored and reversed engineered a CDC Bus and Tag tester. Got the controller schematics (these were also very hard to find). Constructed a ramp to get them inside the house (there are a few steps that we have to get over). Repaired the OS/2 computer for the channel emulator card. Ken has also made an IBM 360 CPU emulator. Apollo is getting priority.

[@idahofur]

I couldn't remember if you or somebody else said they had the card for that. I found that very interesting. I card to hook up your ibm 9 track tape drive to a pc.@@CuriousMarc

[@CuriousMarc]

@@idahofur It takes two cards. I have one of them (the channel card). IBMmuseum has the other card (the 360 CPU), and volunteered to lend it to me.

[@jasonmurawski5877]

Have you repaired this drive? If not will it be its own series/video when you do?

[@CuriousMarc]

Not yet, because I could not bring it into the lab. Now I can, but we must wait for the end of the Covid episode to gather the team again. We are also trying to recover tge schematics of the 360/50. After a long search, we think we have found one copy in Switzerland, but not been able to scan it yet. The IBM 360 is a (very) long term project.

[@jacknedry3925]

I want a good 9-Track tape drive but don’t know where to start, could anyone help? Thanks in advance, Jack

[@rty1955]

Yes, you need to get a 9 track with a SCSI interface. There are many out there, HP, DEC, KENNEDY etc. The other interface (I think it was perkin Elmer interface) is a pain in the A**

[@Membrane556]

I wonder if there are any functional S/360 systems still around?

[@CuriousMarc]

Save for the 2 FPGA replicas I mentioned somewhere else, not to my knowledge. I suspect it's high on the Living Computer Museum to do list though, they have acquired 3 I believe.

[@PWingert1966]

I think the last production model 360 was decommissioned in Canada in the late 90's. I remember reading an article about it somewhere in a computer trade publication of the time.

[@johnlister]

@@CuriousMarc I think it’s a pretty tall order (good luck). If you can't get the hardware, there are System/370 emulators (en.wikipedia.org/wiki/Hercules_(emulator) for example). But real System/370s had channels - separate IO computers - which came in separate boxes, and while the system level of instructions required to program the channels “CCWs” is reasonably well documented, I have never seen the electrical specs for the interfaces between the mainframe and the channel, and the channel and various control units.