Computer Stuff YOU Should Know! 

About 99% of this is over my head, yet I find it absolutely fascinating, and can't wait for more!

Yeah, I'm running the hack to "return RU-vid dislikes" Why would anyone (16 so far) dislike a video like this. No one makes you watch it. There are very few still capable of troubleshooting this old hardware, fewer still willing to. I just don't understand people. Thanks Dave, I know this isn't going to change the world, but it certainly is bringing back memories and showing just how bright the early developers were. I'll be here 'till the end.

Definitely liking the hardware deep dives into the peripheral chips. Interesting to see the deep levels of integration they were able to do and writing small device drivers is one of my favourite things.

These KIM videos have been my favorite of all your videos to date. Tinkering on and investigating old equipment is very interesting.

Another reason for Baudot code to use inverse frequency order is how it was originally input: an operator manually entered each character by pressing (or not pressing) keys on a five-key keyboard, 2 keys under the left hand and 3 under the right. This bit arrangement meant that the most common characters needed the fewest keys pressed to type them.

Loving this KIM1 series Dave. I'm fully liked and subscribed!

Nowadays few people know this. I really appreciate you sharing that vintage architecture. It is a very important video.

Might be he most concise explanation of how ICs are memory mapped I’ve ever seen. Excellent work.

I had a similar computer to the KIM-1 called a TEC-1. Hex keyboard & 7seg displays, only it was Z80 based. My dad had one of those teletypes and I used to save my assembler programs on it. This KIM-1 of yours is bringing back memories.

Your computer history videos are so interesting. That's why I keep coming back to your channel and also why you are my favorite RU-vidr. Keep up the good work, Dave!

Like you it was the first computer I ever got my hands on, also at school, in the UK. We though didn't have a fancy pants teletype terminal. everything was input on the hex keypad and output on the 7-segment based display. Programs were (unreliably) stored on audio tape. Thanks so much, I’m filled with nostalgia. It, and the ZX81 changed my life.

You have connected so many concepts in my mind. Genuinely, thank you for your work and sharing it with us.

Has me thinking about digging out my old KIM and seeing if it still works. Then again the SuperPet is gathering dust too.

Thanks Dave, keep it up. This pre-dates my computer usage by 3 years, but it’s super interesting!

Awsome Dave, really takes me bk, cheers, n enjoying!!!

I do enjoy your videos, keep them coming. I started with a card punch, card sorter, and card reader, with overnight scheduling to run your code, and picking up your output the next day, because the University placed a premium on the use of teletypes to where the students in general could not afford to use them. If I remember right, they had a Burroughs system. Sadly, I had to throw out my paper tape, cards, and the like about 15 years ago in a move. The oldest stuff I got left is a couple of Osbornes (off white/blue edition), with 5 1/4 floppies of some programs and CPM OS. At this point I don't know if any of it still works as floppy disks lose their magnetism over time, but hey, it's cool to have.

Loving the KIM-1 stuff, Dave. Looking forward to the next one.

Loving these deep dives. Thanks for sharing.

The ETAOIN SHRDLU sequence, while indeed reflecting English letter frequency, comes from the keyboard arrangement on the old Linotype typesetting machines, which was also frequency-ordered I guess to help the machine operators set type faster.

For the KIM-1 Microsoft BASIC, you are better off just hitting 'ENTER' at the memory size prompt. It will start and the end of BASIC and probe its way upward until it runs into non-RAM. You can PRINT FRE(0) to see the amount of free space that is available. The only reason you'd want to manually enter a value is if you have code loaded in high upper RAM that you want to make sure BASIC doesn't clobber, but I'd imagine any such RAM wold go in the lower 5K RAM space of the KIM-1.

This is awesome!! I can't wait for the next episode!

Hi Dave, and thanks for sharing your knowledge on these things, and detailed workarounds you done to get things working on KIM-1. Awesome stuff ;-)

I never got serial to work on my KIM-1 using the same Corsham board. I never thought to check if my KIM-1 was modified... I certainly will now! Thanks for the inspiration and great videos

Again, great video, Dave! Thanks!

I was sceptical towards your Channel for too long, Dave. Great work. I'm so gonna use your videos to teach my daughter IT for her GCSE- big thanks. IT Legend

History of these machines is so fascinating. I grew up with a c64 and loved it. Kids today just can’t understand what it was like without these great videos you make.

I LOVE this series! please keep it up

Brilliant, love the content keep up the good work!

I really enjoy the deep dives into this old stuff. As a kid, I remember drooling over the likes of SWTPC, IMSAI, and Vector Graphics, and literally wearing out the Heathkit catalog. I got my BSEE, specializing in digital design. I love these old systems; they are simple enough for someone to understand what's going on.

This is great stuff, thanks for sharing this!

Amazing stuff Dave thank you

First video for me. Loved it immensely! Subbed.

Great video! In middle technical school in the 90’s we were taught about the 8086 and chips surrounding It. But It took them forever to explain what you just did in minutes. Of course you’ll need to know stuff to understand other stuff and I probably didn’t know enough back then. Most certainly i’ll enjoy a deeper dive.

This is pretty cool. I like the deep delve into the history of computing.

Dave, this video (and pretty much all of your others) is pure gold! You know your stuff sir :-)

Loving these KIM videos, please continue exploring! :) This is such rare hardware these days, most people will never see a KIM in real life, much less be able to play with one. Given the tremendous importance of the 6502 chip, and seeing this is how it all began, I consider this important history and treasure every video I get.

Love it Dave. I so wanted a KIM-1 back in the late 70’s. I had to settle for a COSMAC Elf with an RCA 1802 cpu. Keep these videos coming!

Commenting to drive engagement! I am loving this series, keep it up!

Great Video! Like a fire hose if information. You must have been so pumped when that transistor worked ! Congratulations .

Wow. Very cool. I'm in awe!

This is really cool. I'm getting a lot of flashbacks to Ben Eaters breadboard computer. It looks like the KIM was using very similar logic with it's addressing.

pretty cool video!! Brings back memories from the day.

Yay, my day just got better!

One "minor" correction. The Teletype Model 33 ASR (Automatic Send & Receive = paper tape punch and reader) used the American Standard Code for Information Interchange (ASCII). Baudot was used on the earlier version of Model 28 Teletype. Baudot was a 5 bit code. ASCII was an 8 bit code which permitted additional characters, including lower and upper case letters as well as a number of "special" characters. ASCII also included the ability to add parity to the character. Most were 7 bit character plus the 8th bit being parity (usually even).

Dave’s videos are like that scene from the matrix where they just pump information directly into Neo’s brain. “I know Kung Fu”

Good video Dave! Thanks for sharing it with us!👍💖😎JP

Brings back memories. I not only programmed through the ASR-33, but did the maintenance on it, the SEL mainframe to which it was attached and all the associated peripherals (magnetic tape drives, 10MB disk drives, 132 column line printer etc.) back in the mid 70's. This all while in the military. The training and experience I got allowed me later to have a long career in aerospace.

I have always been interested in early computers like the KIM 1 and this was a great explanation! I used to hate math growing up, but since learning about computers and how binary works, I am so fascinated by it. Thanks Dave, great information.

Nice work Dave!

Absolutely do like. I saw my 1st and only KIM-1 strapped to the top of a educational robot in tech college many years ago.

Hardware level videos are always enjoyable.

My final year university project used a SYM-1 (the UK version of the KIM-1) to control a 'robot' chassis - two windscreen wiper motors for movement, ultrasonic and bumper collision detection, hand made encoders for speed and position calculation and all the code was hand assembled and entered via the hex keypad

love this Dave :)

I watch this channel every day even though I understand like 1 out of 10 concepts

Thanks Dave, educational and enjoyable as usual! I have a definitive memory of (seeing my dad…) being able to run communication with old VT 100 much faster than 4800 baud. Now feeling the urge to try to fire up the KIM-1 rev b that I have successfully hidden every time “someone”has wanted to rid the house from useless stuff (-:

I was taught basic on a Teletype ASR 33 attached to a Wang minicomputer. Paper tape was out "mass storage" It was upper case only. It is said some of Unix /Linux's cryptic commands come from avoiding typing much on the Teletype terminals. They had a very heavy keystroke. Pie plates were used to store our coils of paper tape. With the source , basic can be extended freely. Well within the limits of your Ram and rom. I have an Aim 65 . It is essentially, the keyboard extension of the kim. a 20 character display and adding machine like printer are its terminal. It will be great to see more of this historic machine.

Excellent video Dave. Made sense to me. I'm not old enough to have ever used punched tape but I was taught by those who did. My first proper job after university involved assembly language with Zilog Z8 microcontrollers (not to be confused with Z80 microprocessors) and RS232 UARTS and 74LS logic chips and stuff like that. Still looking after some of them today.

I don't understand much about the inner workings of a computer, But I always feel like I understand a tiny bit more after watching you

Hammering the Like button pretty hard over here, bro, would love to see more.

Love these videos Dave. Maybe progress from the Kim1 to the PET, c64, c128 and Amiga, showing how chips improved with each generation. That would be fun.

The joys of system programming. Keep it up!

Great videos , i'm learning a lot from it

Fascinating stuff indeed!

Too cool! Thank you.

KIM-1 used the 6530 RIOT which is a Ram/Rom Input/Output-Timer variant. Atari used by far the most 6532s - probably 30-35 million in 2600s and another few million in 8-bit peripherals.

I am new to Ardino and i understood 70% if this. But its amazing to see this old hardware getting a new life by someone who is so passionate about it. I love the videos!

Thanks Dave!

Very cool and great explanations. Keep up this series if you add a couple more episodes this will only get better.

Wow - that brought back memories of some of my first college gear in the mid -late 80s. Teletypes, papertapes and having to set the memory map. ( that got me into 6502 assembly to get the hardware to read and control external electronics , which paid well for a while)

The teletype makes me think of Saturday afternoons watching the live football scores go past on TV. The screen would be split in 2, and the bottom part(about 1/5th of the screen) would be taken up with a camera pointing at a teletype that would give a printout of the updated score, time of goal and name of the player who scored every time a goal was scored, as well as half time and full time scores. This still goes on this day using digital means on BBC1, but they still pipe in the teletype sounds. Keep in mind for this, there's a TV blackout on football between 3-5pm on Saturdays here. The talk about the RIOT chip makes me think of a C64 tape game that said it used more memory than normally available because it would turn off I/O lines the game didn't need to gain a bit of RAM back without bank switching. I assume that this is related to how the RIOT(or CIA in this case) is mapped into the memory addresses. I still have that game on tape, but I can't play it without using an emulator because I lost the copy protection booklet.

Ah brings back memories of converting a KSR 33 with dial-up modem to current loop used by all the SEL computers we were running back in the day. The interesting things you find out they did to make one system work and then backing those changes out.

Originally, the ASR/KSR 33 Teletype 33 came with a 20 mA "current loop" serial interface. This allowed fairly long (100s of feet?) cables to be used to drive it. VT220 were actually the fourth generation of "glass teletype" from Digital Equipment Corporation (DEC). The followed the VT05, the VT50/52 and the VT100 family.

We used paper tapes on our high speed IBM printers back in the early 70s, hooked up to a 1401 (1) and the 360-160 (3)

This is where the real magic lives! I learned about these chips with Atari and Apple computers. I love this stuff and it has come in handy many times fixing things. Older industrial gear remains useful and these topics speaks to what one needs to fix and use that gear. Too much fun Dave!

Keep plowin! Love this series.

Excellent overview of memory decoding, as many other things

Definitely interest in more of this series here.

Keep going Dave!!

Really enjoying this content. I do wonder tho how successful it will be worth the younger generations vs your staff racing series and the to like. Ah well. We will enjoy it while it lasts

excellent breakdown of the KIM's 6530s function and how memory is addressed on the KIM. I learned new things today, thanks. I would like to add that the extra 128 bytes of RAM was critically important to some programmers. A text adventure game for the bare KIM is Kim-Venture written by Bob Leedom in the 70's uses all of the 1152 bytes available minus six bytes. It was hand complied by the author and is a masterpiece of coding efficiency.

Dave,please keep your excellent videos coming. Stuart from Melbourne AU

Ahhhh now this is cool. I can't resist old hardware!

My first computer, great video!

This is some useful knowledge for my recently completed RC2014(z80 solder yourself kit).

dave I am certainly enjoying this deep dive into the kim-1! I wish I could get my RevE to work!

We used a KIM-1 for the Modern Physics lab. Programs were stored on cassette tape (on a Radio Shack player). I remember copying the program and typing it into the KIM-1, messing up and having to start over (because it couldn't read the program last stored on the tape- gah!).

Hello Dave, I really like and enjoy your videos, and also your book about autism. I have never thought about it too much, but it is very interesting to read your very detailed description and explanition of your thoughts of autism, and how well you have analyzed your personal thoughts about it. I am a retired electrical engineer and learned to program when only Fortran was taught and Basic was brand new. we had to program Fortran on a coding sheet and then have it punched for input on paper tape or cards by the key-punch operater. Machine language was also around, of course, and Assembly. My interest was circuit design (TTL & analog), System design and RF fields and waves. I have built a lot of systems around DEC PDP/11s, VAX 780s, Data General and ModComp computers. I was also a HAM a long time ago, and one had to learn Morse code. I believe your questions about inverse character utilization and holes punched in paper tape relate back to sending code. It was important to send code at a high rate, and this was more quickly sent by the most- used characters being the shortest, i.e. the ' E ' and such. Maybe some others have mentioned this, but it seems so obvious to an old HAM! Congratulations on a great career, MS-DOS and Windows development and your many accomplishments with MicroSoft. It appears to me, that your eye-contact is perfect.! Keep Up the GOOD Work!

3:20 "fewer holes are better" without knowing the construction, I'd assume that every paper chip has a chance to go somewhere it shouldn't. So fewer paper chips might also mean longer service intervals.

This series is very interesting to me. I was born in 78 but I remember the TRS80 era machines. It's amazing what humanity had to go through to get to super computers in our pockets

There is interest. Thank you and glory to The Algorithm! May the interactions with your videos help spread the channel across RU-vid!

Just gave Inverse frequency a few minutes and came up with the following list - Fewer Holes means: Stronger Tapes Faster Printing 1) Based on original manual keying method Faster Printing 2) Better waste management with fewer 'dots' to exhaust (less manual emptying) Faster Printing 3) Better Temperature management on punch solenoids Fewer write errors (miss-punched - based on a fixed error rate) Fewer read errors (obscured holes - based on a fixed error rate) Better Longevity on write punch equipment.

Well done!

Kim One and the Riot Chips is such a good name for a math rock band

Love this series. Love the fact you played with sexy Amiga's. I have worked with A500 & A4000T, still have a running A1200

We had a number of Teletypes that we used to load programs into a DEC PDP-8. The tapes were fragile, especially when loaded contently. We ended up using Mylar tape for many of the programs. they were tough to punch, but survived

I like this series a lot. I was 13 when the KIM-1 came out, but did not get interested in electronics until I was around 16-17 y/o. Then because I loved arcade games, I got interested in computers and bought a TRS-80 Color Computer w/ 4K RAM for $399 in late 1981 early 1982. Loved computers/electronics ever since and I became a programmer. Even though I never owned a KIM-1 I love learning about computers from this era -- including the SWTPC 6800, Altair and IMSAI computers. You should get those as well and do a series on them!! :) :) :) ...

Baudot code is a perfect example of variable length encoding, allowing for efficient serial transmission / increasing transfer speed of English language-specific content. Another example of the variable length encoding is Morse code.

Happy days at college, programming my BBC Micro's PIO User Port at address &FE60, with the Data Direction Register (DDR) at &FE62 - and all in 6502 assembler. Thirty-five years later, and I can still hook up my old college project (a simple spoken command interpreter), to that same BBC Micro, loading the code from the same floppies - and everything still works like a dream.

Fascinating. I think the oldest machine I have fond memories of using was the TRS-80 model 2.

I used this Teletype in 1974 and HP basic at the uiversity. That was exciting.