I Bought the Cheapest Altair 8800 Computer on Ebay

you got a $2,000 Al yep ain't it pretty that wasn't the word that came to mind it's uh a little shop born but that's why it was cheap you know how much Alters cost I think about 6,000 bucks or so wait how do you know that well I'm your conscience you know I hear stuff but you should be proud of me of us we saved 4,000 bucks or another way of looking at it we wasted 2,000 bucks I mean look at this disaster the front panels all scratched up it's got the wrong cards the wrong back plane the wrong power supply wouldn't we be better to just save up 6 grand and get something you know OG why pay retail when you can get the same functionality for a discount ah yeah why order a Gucci watch from Gucci when you can order it from wish instead the difference is this is an Al te and it's the cheapest one I've seen on eBay in years 2,000 bucks and we can play kill the bit and listen to Fool on the Hill same as all the other Al guys there's something awfully appropriate about playing that song on this thing why you got to be such a down because I remember your past $2,000 Adventures remember that $2,000 Chevy Bel a uh well and then that $2,000 edel I was going to fix that and the other $2,000 Edo but it did run so did anyone near it come to think of it wait what are you doing running away I don't want to be within 5 miles when you plug that thing in ah what a wimp I bet you Pur like a kitten here let's power up and show conscience the power of the thrift economy uh-oh hey conscience went [Music] up yeah I did a thing again well a thing I did before the thing I did in a previous video um right a while back I bought eBay's cheapest alter and yeah it's not perfect as we'll soon see but if you're an apate historian like me it doesn't matter quote unquote cheap as it was this is a real Bonafide alter 8800 the history of the mits Alti 8800 has been covered in various professional documentaries and countless Publications it's often credited by journalists and such as the first personal computer I'm sure most of my hardcore vintage computer viewers here know all the details and all the stories about this legendary machine but just for posterity or for the benefit of those who have no idea what this computer was all about here's some background first let's set something straight the alter 8800 contrary to the belief of many was not the first personal or microcomputer actually it wasn't even the third there were several microcomputers and or personal computers on the scene before the alter debuted at the beginning of 1975 take the microcomputer machine's mcm7 for example which arrived in 1973 this machine looked like something from 10 years into the future with a complete keyboard screen and cassette based storage all the stuff the alter didn't have as originally designed the mcm7 was mainly for scientists though and ran APL and it was really expensive and sold in very small numbers and it was Canadian so yeah that's why it doesn't get a lot of Glory as for more personal computers that predated the alter well how about the Mark 8 mini computer which appeared on the cover of Radio Electronics months before the alter was announced powered by an Intel 808 running at either 500 or 800 HZ the mark was a kit only in the sense that you could order a set of pcbs you had to find all the other parts all by your damn self there was no company behind it just an Earnest graduate student in engineering apart from support from other hobbyists you're pretty much on your own with no warranty or guarantee whatsoever micro instrumentation in Telemetry systems AKA mits however was a real honest to goodness manufacturing output who could achieve some economies of scale its founder and owner Ed Roberts knew a thing or two about producing electronics at an affordable price given his recent experience producing lowcost calculator kits it was the decline of that business that prompted Roberts to look at the newly invented microcomputer as a way to calm his Bankers down mits would not just offer a set of plans or maybe a few pcbs and a magazine article they would provide a complete professionally manufactured kit with all the parts required and excellent documentation to go along with it they even offered to assemble it for you if you so desired for a fee the quality of their kits would be a step above anything that had come before another another Advantage alter had over its predecessors was timing the alter was introduced just as the new Intel 8080 CPU was hitting the scene this was an 8 bit 2 MHz microprocessor that could address up to 64 Koby of ram making it far more useful than the Intel 808 to build a practical computer around around the same time Le Solomon editor of popular Electronics have been making noises about wanting to feature a professionally manufactured computer kit in his magazine the alter's selection as the cover article for the January 197 75 Edition no doubt provided a major boost once assembled the alter 8800 was as basic a computer as you could get it featured an Intel 880 running at 2 MHz as little as 256 bytes of ram professionally manufactured metal chassis power supply and mini computer style front panel with switches and lights it didn't look anything like what we would think of as a computer today no keyboard no monitor not even a way to save your work something that left hobbyists at the tender mercy of their power providers no yes as originally offered the alter was little more than a glorified trainer a minimal computer designed to teach microcomputer fundamentals you weren't going to be playing pong on this thing or typing in an essay not that that mattered to hobbyists who were just excited to have a complete computer kit of decent quality to scratch their digital itch some hobbyists upon hearing of the alter's existence literally camped outside in ms's parking lot for days waiting to receive one at $439 as a kit or $621 assembled the alter certainly wasn't cheap but at least it was within the financial reach of the average person perhaps the alter's greatest Ace in the whole was the expansion bus it offered dubbed the alter bus and later standardized as the S100 bus it featured 100 pin plug-in slots and ultimately became the first industry standard expansion bus for a home computer the CPU RAM and later expansion boards were installed as removable cards which made assembly repair and future upgrades easier than onp pass machines the alter buus certainly wasn't a perfect design but prior to its existence early computer users had had to work delicately around thickets of wires and install components of their own or someone else's design praying the whole way that nothing was broken in the process the alter bus on the other hand required little more than buying Andor assembling a card installing it and maybe a little bit of tweaking with much less fuss this undoubtedly helped in the evolution of personal Computing from something mainly of interest to those well- versed in electronic and Science and into the realm of the general consumer the alter bus coupled with mit's excellent timing helped create a cottage industry of thirdparty Hardware providers for the alter who together with mits help transform the alter from a minimalist trainer into a full-blown practical computer with upgrades like serial boards video boards peripheral boards and so on it's difficult to overstate the alter's historical impact so many hobbyists had their first experiences with programming Games music and peripherals on an alter who knows how many future careers in technology began flipping switches on its front panel many a computer club meeting was arranged to swap notes experiment and support it numerous luminaries of the computer industry were inspired by it to take their own leaps of faith into the technology industry not too many computers can say they had a hand in the creation of a nearly $3 trillion doll giant like Microsoft which owes its success in no small part to the basic they were invited to produce for the alter yes the alter 88800 wasn't the first and no it wasn't the best computer but it was the right product at the right time and its features timing and cultural impact secured an important place for itself and its maker in history yeah mits had started a revolution but their time in the sun would be shortlived for like apple later on with its Apple 2 and IBM with the 5150 PC they had created something that was somewhat easily copied some of the seeds of the alter's decline were sewn when mitz attempted to create a 4 KOB dynamic ramboard system development problems ensued in ACC combination of delays and lack of reliability created opportunities for competitors including those that came up with their own better designed Ram Board companies that had been producing improvements and peripherals for the alair soon started coming up with their own complete systems systems that were better a little cheaper sometimes and more reliable mits quickly lost control of their invention the company did produce successors to the alter but cash flow was a persistent problem competitors were many and the stress of managing it all was cited by Ed Roberts as a main reason for eventually selling to another technology company called pertek pertek purchased Ms in the hopes of acquiring the rights to alter basic which Roberts's company had spent nearly a million dollars developing after the initial design by Microsoft's Bill Gates and Paul Allen Roberts felt alter basic rightly belonged to mits and was theirs to sell but Microsoft argued that they were the rightful owners of the code and an arbitrator unfortunately agreed pertek continued to sell the alter but within a few years both mitz and the alter name would be retired by pertek for good despite no longer being produced the alter was not gone by any means it was just biting its time waiting for the moment when historians and collectors like me would begin to give it its due and that moment is right [Music] now like many other collectible computer systems the alter has a few variations some worth much more than others if you're willing to accept some trade-offs you can can collect rare machines like this somewhat affordably anyway let's take a look at the different versions of alars out there now I should be careful here I am not an expert per se on mits or its products what I do know has been gleaned from research and observation of many auctions over the years involving mits products so take what I say with a healthy grain of salt and feel free to correct me in the comments I don't think anyone really has a complete picture on alter production and mits were not always consistent in what parts they use from system to system later on so you have to approach buying one with caution and a sharp eye the very first alter 8800 model is what's known to collectors as the revzero just like the Apple 2 rev zero it is called such because it's the original product before any changes happened okay technically perhaps the Rev zero is more like a REV one as it is actually not the first original design mitz proposed and prototyped the original was a compact stacked pile of boards with no alter bus connectors in sight I'm not sure if this design made it into the legendary prototype which was shipped to Les Solomon for testing and inclusion into popular Electronics the Prototype fell victim to a male strike in 1974 and was lost in transit and there just aren't any pictures of it out there the unit that appeared on Popular electronics's cover was just a hollow box but as far as I know all future prototypes and production machines followed the more familiar design that we know with the horizontal back plane that individual cards plugged into the Rev zero is the machine that collectors covet most and that's typically how it is in collecting people usually like the very first original thing as it was delivered by the manufacturer and in good condition an alter can fetch easily north of $6,000 or more there's one machine I'm pretty sure was worth more than 6,000 bucks formerly owned by Craig solomonson if you want to see what one of the very first alter 8800s off the production line look like check out this video by Craig in it he shows off a machine with serial number five you don't get much more original or basic or lower serial number than this like Craigs most Alters have a sticker number at the back although some doubtless have fallen off and some collectors actually didn't bother to fix it to their machines in the first place like many companies mits opted not to start their serial numbering scheme at number one the serial numbers are six digits starting with 22 the rest being the sequential number of the machine or at least I think it is it's a bit confusing because while significant changes to alter Hardware broadly aligned with increases in serial numbers I've occasionally seen later machines like the alter 88 00a with very low serial numbers perhaps those machines were upgraded or maybe the numbers aren't truly sequential I'm not sure anyway Craigs machine if we can trust the earliest serial numbers is 22005 and in his video he says that makes it the fifth built so that's pretty darn early add to the fact that the serial number was suffixed with an a meaning it was assembled by the factory and that makes it even rarer actually you can kind of tell this machine was built by the factory just by how neat and TIY the wiring and everything is even the front panel on this very early machine differs from most of the rest note how the silk screening has a straight line from the sense switch text through seven address switches this design seems to have persisted through at least, 1600 units later all Tears like mine have a diagonal line that connects with another line underneath as far as I've been able to determine most all tears were actually sold as kits and their serial numbers are suffixed with K given that it costs 50% more to have an alterar assembled by mits or around $1,150 in today's money it's understandable that a lot of people opted to go the kit route however like many projects requiring lots of time persistence attention to detail and skill many alair kits never reached a working State a co-owner of a computer store in Atlanta that sold alter kits Ron Roberts no relation to Ed was quoted by the Atlanta Journal saying kit building quote wasn't for the faint of heart even if you succeeded in putting an alter together chances are it wouldn't work Roberts went on to estimate that something like 2third of all kit built alars sold by his store were never finished or were but simply didn't operate and that tracks with the smattering of Kit parts that I bought way back when clearly someone started the project and then abruptly stopped for some unknown reason perhaps lack of Interest or a better product that came out later on mit's manuals were generally excellent but with something this complex it was pretty easy to make costly mistakes if the overall failure rate was any near as high as what Ron Roberts suggested that could help explain today's scarcity of Al tears and butress higher prices there's a lot of empty space inside a stock alter basic machine only really needed the RAM and CPU cards to be functional Craigs however had an extra Ram Board as well as a serial board one negative aspect of the original alter though was its power supply this mess of Transformers and caps were known to be rather weak while present day collectors insist on its presence for original many contemporary users were only too happy to upgrade if they got the chance especially if they were adding multiple boards to their system and if they did that does take away some dollars on auction value today the revzero alter's cards are distinctive apart from having revzero etched right onto the PCB their silk screening is done in yellow later revisions of the alter cards had black silk screening I've done some of my own research watching sales on eBay and it seems like there were roughly around 3,000 or less revzero machines somewhere near or after serial number 223 00 mitz released the Rev 1 which was essentially the same machine except the cards were made thicker to reduce warpage along with some minor tweaks to fix bugs in the foil patterns so rev 1es really were a minor tweak compared to the Rev zero although collectors draw a bright red line between them on value these machines typically fetch 3 or $4,000 in good condition however after the Rev one the alair did begin to change substantially the alter 8800a which appeared I think somewhere around serial number 5000 featured a revised front panel badge as well as a larger back plane rather than relying on individual four- slot back planes that had to be wired together as you expand it the power supply was also revised to a stronger single Transformer design and sometimes the front panel switches are flat and paddle-shaped 8800a prices fluctuate a lot depending on condition I've often seen them go for well under $2,000 after the 8800a came the 8800b which featured an allnew front panel with paddle style switches an 18 slot back plane and redesigned CPU card with new Intel chipset it also came with a Serial card something the original 8800 forced the user to buy separately the 8800b definitely has its fans and I've seen them fetch a bit more than the 8800a often over $2,000 people really seem to like the revised front panel design the 8800b was followed by the 8800b turn key this was a significant departure from the original as it eliminated the whole Blinky lights and switches front pan panel Paradigm in favor of a literal turnable key on the front the turnkey had a special card called wait for it the turnkey card that contained boot ROMs for the machine so all you had to do was hook up a terminal and disc drive and go some contemporary hobbyists scorn this machine calling it The Turkey because they didn't like the lack of a front panel today's collectors also seem to agree at auction the turnkey fetches much less money than a REV zero alter or even an alter 8800a and in recent years I've seen a bunch go for less than $11,000 there was also an Altera variant known as the 8800b turnkey Foley Edition so named because it was sold through a department store chain called folies for this unit the alter chassis was modified to hold one or two minidisk floppy drives I've only seen a couple of these come up for sale and there's no stable price for them I've seen them go for upwards of 2 Grand though if I had my DRS I'd probably own every model made but this isn't a perfect world and resources are scarce so I focused my attention on the original pre 8800a alter of course I'd love to own a pristine low serial number rev zero alter but uh I also like to [Music] eat a couple of years ago I stumbled on an estate sale offering on eBay it was for several pieces of an alterer 8800 although not nearly all of it from what I could see it appeared to be bits of a low serial revzero alter with early version of the manual a REV zero CPU and a front panel card outer cover and some unopened packages of M's famous angel hair white wire I made what I thought was a lowball offer because alars are pretty popular and expensive and I got it turns out I should have offered a lot less anyway it appeared the original owner briefly started the construction process and then for some reason or other stopped and the rest of the parts were lost to time but it was a way for me to get my hands on actual alter stuff so I wanted to ride I felt like I was touching the Holy Grail I then put out an appeal to viewers in case I might have some spare parts for Alters lying around particularly the internal chassis and one viewer sprung into action he had a complete alter 8800b internal chassis with back plane and power supply unit he offered for a very reasonable price bet I jumped on that but for the next 2 years I was sty made although alter 8800 parts do show up on eBay from time to time they are few and far between and over time their prices have risen along with complete systems one component I really needed was the front dress panel with all the switch labelings and stuff the literal face of the alter but in 2 years of looking only one of those ever showed up and of course eBay being eBay it went for several hundred bucks also during that time I never saw an original alter power supply come up for sale and the original back plane well let's just say some sellers are kind of out there so Along Comes one particular Christmas and behold this baby shows up interestingly the Christmas holiday can actually be a pretty good time for deals on eBay I think part of it is potential biders being exhausted from their Christmas spending and too busy with holiday stuff to partake one Christmas holiday I scored a complete Swift PC 6800 system with TV typewriter 2 Terminal ac30 cassette interface and manual for less than any one of those components would have sold for individually this alter 8800 was complete and possibly functional but there were some big caveats for one it was missing the famous 8800 label on the front some hobbyists didn't bother with those but collectors seem to prefer to have them second it had an aftermarket back plane third it had an aftermarket power supply in terms of original Al Parts it definitely was a bit of a mixed bag the front panel was a REV 1 while the CPU and RAM cards were both rev zero I asked the seller about this and he told me that he had had a REV zero machine also and for some reason or other swapped in the CPU and RAM card from that into this rev 1 machine and then then did something else with the original rev one card and that's okay contemporaneous users of the all teror did part swaps all the time the point is for my cheap skate eyes it's fine just like it is it was listed the week of Christmas there was only one bit on it and I figured what the hell counting on the exhaustion of Christmas shopping I put in a lowball bid via gixen and I left it if it was going to go for much more than that H I simply couldn't afford it anyway the auction ended my snipe bid went off and no other snipe bids fantastic I just bought the cheapest Al I'd seen on eBay in at least 5 years I can't tell you how cool it is to finally have this machine in my possession for so long I was only able to look at it in pictures or other people's videos because of the insane prices they fetched it's so weird seeing an actual alt on my desk after years of just reading and thinking about owning one it's so iconic okay so it's not completely original spec but who cares this is a real alar front panel a real alter case and there's a real alter CPU and RAM card inside that's the true alter everything else is not that important to me now while I was hunting for parts for my 8800 a really awesome fellow hobbyist reached out to me and offered me an alter front panel badge it was unused near mint condition except for a dent in the end so yeah that's going on this Beast right now there we go now we're legit okay so let's have a look at the actual Hardware externally this alter checks off all the boxes there's nothing here that isn't legit mits we can see the serial number is just a wee bit over that 300ish border between rev0 and rev 1 however as I said before alter cereals are not 100% indicative of what the hardware should be inside I've seen rev zero Parts in machines with higher serial numbers and I've seen rev one Parts in machines with lower serial numbers like most companies mits with pragmatic about clearing its parts inventories the inside is nice and tidy and we can see right away how the previous owner dispensed with M's much weaker power supply the original power supply featured three different Transformers and a PCB that hosted a whole bunch of axial capacitors this Arrangement worked but just barely and ass serious alter users began using their machines as honest to goodness computers especially with multiple expansions the limitations of the original Power Supply became painfully obvious I can't say for sure if the original Supply was ever here I note in the manual while the Builder did check off various boxes during the construction process else Ware the section covering the power supply is devoid of any of that it's quite possible by now users were wise to the 8800 power suppli is failings and opted to emit that and create their own yeah this one is seriously beefy the box of big capacitors here makes me think of a really well constructed bomb the back plane board here I don't think is original mits either it's nine slots and I don't see any manufacturer marking you can see that the mits units were quite a bit wider than what's in my machine and have more holes drilled for card guides and such there might be manufacturer markings underneath but I'm not messing with this right now when I got the machine a few wires had been broken off on both the front panel and front panel connector and it seemed pretty obvious where they'd come from so I resered those the seller informed me that the beefier power supply puts out plus 10 volts instead of Plus 8 volts on one of the rails and thus the regulator on the CPU board had to be modified with a long long heat sink to dissipate the extra heat as it was brought down to 5 Vols he also added a large fan at the back which makes the occasional disturbing noises the CPU card is an authentic rev zero card these sell for over 600 bucks on eBay unless they're sold by me yeah I guess I should mention to help Finance this I kind of sold off some of the parts from my kit Parts including my unfinished rev zero CPU card it went for much less than I expected and yeah I didn't expect it to go for full pop since it was missing the CPU but still a few hundred would have been nice there does seem to be a penalty also from selling outside the US another thing I sold off was the original Ram card and I regret this because it had the full 1K installed there's kind of a weird inverse relationship with these cards between the value and the amount of RAM installed the less original RAM installed the more they seem to go for yeah I don't get it either I guess some collectors figure that if there's less RAM on there that means the board was earlier since Ram was much more expensive at the beginning of the altera's existence anyway the top end price for these is about 600 bucks I only got 100ish for mine though H this card was missing a ram chip which the owner removed because it was bad these are 256k by 4 bit RAM chips so you need to have them installed in pairs since I was missing one I removed the chip it was paired with also that brings us down to 768 bytes I think yay but you know that's still a little bit more than what the typical first generation Al ter user had okay so let's put things back together here and then we'll take it for a test spin I haven't really tested this thing full on after repairing wires and verifying that it didn't immediately burn with the application of power I put it away and moved on to other things but today we're going to push our luck a bit and see what it was like to program an Al hair off the front panel I want to stress here I am not and have never presented myself as an expert and I may be wrong on some of what follows actually since this is me we're talking about there's absolutely going to be some things I get wrong I don't program and I only know enough Hardware wise to get myself into and sometimes out of trouble so I'll just give a brief overview of the front panel operation and then start entering programs to get a much more in-depth and accurate look at Al 8800 use I very strongly recommend you check out my VC friend dramp 5113 Channel which goes into Al 8800 operation in much greater detail and shows some really interesting use situations like all te basic with a teletype [Music] so here's the alter 8800 front panel and it is kind of intimidating looking the alter is in some ways to Modern computers Like the Model T is to Modern cars they both do more or less the same thing but each are operated very differently longtime viewers of the channel might remember a video I produced about the OSI 300 trainer board that machine also had a front panel however with OSI the data and address switches were set up to correspond with binary numbers that's because the OSI machine only had a measly 128 bytes of ram so the complexity of programs were very limited however for the alter a user could configure their machine with a kilobyte or even more that makes binary switches and lights impractical so mitz kind of borrowed from earlier mini computer and Mainframe panels and went with octal octal is a base 8 numeral system rather than going from 1 to 10 as in decimal octal's lowest digit is zero and the highest digit is seven with respect to computers a word is a unit of data used by the certain processor design for machines that had word sizes divisible by three I.E 6 12 24 or 36 bit words octal was convenient since each octal digit could represent three binary digits so two four or 12 octal digits could display an entire machine word in a compact way the Intel 880 microprocessor uses 8 bit words so octal is a little less than ideal here all of the data and address lights represent octal digits which can be confusing if you're like me and are used to Binary switches and indicator lights I think Ed Roberts designed the alterity as octal just out of familiarity more than anything else anyway on the alter front panel we just have a single row of Dual Purpose switches for address and data entry so you have to be kind of attentive to which function you're trying to do while setting them the highest octal number used on the alter is 377 which is equivalent to Binary 11111111 the highest value for an 8bit bite of data thus the alter uses only eight switches for entering data rather than nine the other switches are typically used for memory addressing although on a basic 256 byte alter you didn't really need them some of the switches are what are called sense switches these eight switches which you can see are grouped together by the silk screen can actually be read and used as an input device with running programs which we'll demonstrate later on many vintage alts you'll often see colored plastic boots put onto the ends of the alter switches to make it easier to group them together for different function functions on the bottom of the front panel we have the power switch a switch that tells the computer to run programs or stop running a program a switch that allows us to step through instructions one memory cycle at a time a switch that allows us to examine the contents of a selected memory address or examine the contents of the next memory address a switch that allows us to deposit data to the current memory address or deposit it to the next address a switch that allows us to reset the CPU switch that protects Ram from being overwritten if the memory board supports it and then finally two auxiliary switches which were almost never used the data and memory LEDs as I mentioned are grouped in threes except for the data LEDs which have only eight there's also several LEDs that indicate the status of the machine and various things like if memory protect mode is activated again I'm not going to Dive In Too Deep with these as other people like damp explain these functions much better than I can data entry is pretty simple you can choose the memory address you want to go to first and then hit examine to go there then you can set the data switches to the octal value representing the bite you want to deposit and flip up the deposit switch the difference between deposit and deposit next as mentioned is deposit places the data into the memory address you're at now whereas deposit next puts the data in the next address up from where you currently are in many programming situations when you're starting from scratch you usually will reset to go to address zero choose the data you want to put there which would be an instruction for the CPU typically and then hit deposit then you would put in the next bite of data and hit deposit next to deposit the that data into memory address one and then typically a programmer would just keep entering new data values and hitting deposit next until done unless they needed to go to a specific address that wasn't immediately above the one that they were working on for their next entry so for a little test drive here we're going to do a basic addition program which will take the contents of two memory locations add them together and then store the result at a location and memory we specify this is provided from the alter's own manual which contains several small example programs like these to familiarize the user with entering and examining data and make the computer actually do something one thing I'd like to note about the alter manual is just how detailed it is the manual doesn't assume you're an electronics engineer and provides plenty of background in a language that most can understand it even gets into the history of logic how binary works and so on It's A Cut Above what passes for a manual nowadays looking at our program here we can see that they're showing something called a bit pattern this pattern physically aligns with the data switches on the alars front panel the manual could just give us the the octal numbers but this is written for beginners so they're basically showing us what pattern of switches would equal the octal number we're seeking in this case 00111 010 is equivalent to octal 72 I think mitz is just trying not to overwhelm the first-time user with math in the first two pages of their guide all right so let's have a look at our program here and see what it does exactly essentially we are loading the accumulator with the contents of memory address 128 why 128 uh no particular reason it's just an arbitrary location mid is chosen for this demo program that isn't smack in the middle of the program itself the contents of 128 are the first number to be added next we move the accumulator to register B we then load the accumulator with the contents of memory address 129 this being the second number which is to be added to the first in the next instruction the computer must add register B to the accumulator which has the effect of adding the two numbers together next we store the result at a third memory location 130 and then finally we have the CP you just jump back to the first instruction of the program to fetch our addition result we have to manually stop the computer program from running and then examine memory address 130 to get the result all right let's hit it first I power the machine up no explosions always grateful for that next we do a full reset as you can see we're at address zero because none of the address lights are lit up this may be confusing for beginners because note there's an address indicator light that says a z which the average person might think should be lit since we're at address Z nope that's octal and if that light were lit we'd be at address one as you'll soon see okay so first bit pattern starting at address zero is 00111 01 0 which is the instruction to load the accumulator the next bit pattern tells the computer where to find the data to load into set accumulator the next bit pattern is all zeros because two bytes are required for the entry of memory addresses since we're not working with any memory addresses above octal 377 we just leave the second bite at zero next we tell the alter to move the accumulator to register B now we load that [Music] register with the contents of memory address 129 which is octal [Music] 2011 and again the second bite is zero now we tell the machine to add register B to the accumulator next we store the accumulator [Music] contents at memory address 130 which is octal 202 again zeros for the second bite and now we issue a jump command back to address zero and again all zeros for the second bite okay so now I'm going to verify I entered everything correctly I'll return all the switches to zero and then hit examine to check the contents there yep matches what the bit pattern should be here now I'll examine next and yeah we'll just keep checking along here that's good that's good also good very good good good good good very good excellent exactly awesome Flawless okay program is good to go now let's give it some numbers to work with first I'll go to address 128 and for now I'll keep it simple and choose the number one that'll be the first number to add bear in mind this is all an octal but octal digits and decimal digits are the same up to seven I'll just leave the data switches as they are and hit deposit next next to deposit one to memory address 129 which is the next location for our data to be added and that will be the second number to be added together with the first all right time to do some math here I hit the Run switch and yeah it's just basically continuously adding one in one here and I kind of do that myself sometimes the manual says to wait a little bit but really this should be done almost instantaneously given how small the program is and now we'll stop it now to check address 130 to see what our result was and check it out we have a two awesome so this is sort of working I'm going to change the contents at 128 and 129 here and just try adding different numbers uh-oh I just spotted a problem as I'm editing here now remember I said to keep your wits about you with these Dual Purpose address and data entry switches well here's exhibit a while I was filming the input of two and three to be added I didn't clue in that I had accidentally left the A7 SL D7 7 switch up which was left over from when I went to examine address 202 or decimal 130 so when I thought I was entering an octal 002 I was actually inadvertently entering octal 202 likewise for three because the machine came up with a result of octal 005 I mistakenly thought everything had worked however as you know the maximum value that can be represented in an 8bit bite is 255 or 377 octal which is why the leftmost set of data switches only have two switches rather than three since the result of adding octal 202 and 203 results in octal 45 we have a problem because that's a higher value than the alter can store in a single bite of data I'm told this should roll the result over to zero but it looks like in our case the alter just added the two and three and came up with octal 005 which kind of fooled me do anyway let's try this again uh this time I'll add octal 4 and three and I'll make sure I don't accidentally leave the A7 SL D7 switch up and we'll run [Music] it yeah there we go okay so yeah this alair is definitely working despite the monkey operating it not working very well this is a valuable lesson in paying close attention to what you're doing okay for our next trick we'll do something a bit more advanced this is something that comes as close to an arcade game as you can get on the original vanilla Al hater created by Dean McDaniel in 1975 kill the bit causes several address indicator lights to flash and sequence this is where the scent switches become useful your goal is to flip one of the scent switches up and down just as the light directly above it illuminates causing the moving LED bit to go dark this is how you kill the bit if you miss the program adds more bits AKA LEDs that you now have to kill now I'll run through it here and again I get tripped up by switch panel confusion a lot in another 20 minute not tying I goofed on entering 010 octal at two memory locations I accidentally read it as the bit pattern as I'd seen in the Altera manual rather than actually octal 010 which is the number two so by accident I'd set the first two switches to zero the second set to two and the final three to zero when in fact they should have been 00 0 00 1 00 oops anyway with that corrected At Last I can run the program and it works it's not super fast here so it's fairly easy to beat but still it's pretty amazing Dean pulled this off at all given how limited the front panel interface is now to turn up the heat a little bit more here I'm going to increase the speed by increasing the value in memory location 6 and we'll run it wow yeah that's way faster uh I'm actually having trouble now H yeah it's just pure luck that I'm able to stop it all right well that's the famous kill the bit Pro program by Dean McDaniel now there is one more really famous alter program I've always wanted to try in person this one involves music yep that's right music no the altar doesn't have a speaker or anything approaching a sound card the music is achieved in kind of a roundabout way The Story Goes that a member of The Homebrew Computer Club Steve dumpier discovered by accident that the alter could produce a kind of music with the help of a portable radio Steve was a very enthusiastic and early alter user such that 30 hours after after his arrived in the mail he had it built and running anyway Steve said he had his alter program to do some sort of sorting program and while running the program was listening to a weather broadcast on a transistor radio he had on hand Steve noticed that when the alter was running he could hear different tones his interference on the radio he then got curious and decided to see if the tones changed with different programs and spent hours toggling in other programs to see what notes they produced cut I a breeze4 we're a budget here people all right reset After figuring out how different operations created different notes he wrote his own program to purposely try to control and manipulate the tones writing what is probably the very first program to create music on a personal computer looking for examples to demonstrate his program Steve picked the Fool on the Hill by The Beatles when he played it for assembled members of the Bay Area amateur users group and Homebrew Computer Club they were astonished it seems like the radio was pretty much the first pereral used with a personal computer anyway that's the story and I've always wanted to try it out in real life now with an actual alter on my desk I figured what the heck one thing I don't have hanging around in abundance are portable radios to be honest sitting here in 2023 I can't remember the last time I actually listened to a radio at all usually in my car I have my music playing via Bluetooth from my phone in fact the closest thing I have to a portable radio is my ancient bedside alarm clock radio here and after many years of neglect the radio portions a little touchy so here's the thing I went ahead and entered the program which on these switches takes a fair amount of time like upwards of 25 minutes however at the end I had no music I fiddled and fettled around but no dice at one point I could kind of hear something like a computer Tone If I kind of just Twisted the dial a little bit towards certain stations but yeah it wasn't changing so what was going on well at first I thought it maybe was just my crappy radio but the next day after talking to the helpful folks on the VC fed forums I realized I'd missed something critically important in entering the data into the alter and this was compounded by a mistake in the comments for the program note here where Steve's notes say be sure to load the starting address into H&L at address 2 and three well that caused immediate confusion because reading the program listing on the left side the starting address was to be loaded into memory locations 1 and two after confirming this error I then made an even bigger error you see despite my Valiant attempts at this thing called reading I had read how the alter deposited memory contents wrong I thought to start programming from scratch you did a reset and then just started entering the contents for the first memory address and toggle deposit next nope when starting at memory address zero you hit deposit not deposit next then you toggle in the memory contents for address 001 and then hit deposit next deposit next always puts whatever data you've specified into the next address there's no way to use deposit next with address zero because there's nothing before it I had misread the function of the deposit next in my brain as it deposits at the memory address you're at first and then carries on depositing to each subsequent address because of this mistake I wrongly believe the program listing was incorrect and that Steve's comments were correct because since I was always hitting deposit next for the first memory address it was always was depositing a memory location 001 in other words I didn't think there was an actual memory location Zer so I foolishly altered the program listing to match what I thought should be happening with the alter and wasted 25 minutes and that's why I had no music anyway the next morning suitably chased I restored the program to its original correct listing I also decided to sub in my mom and dad's old stereo deck on the radio end because its AM radio functions work better and the tuner had more finite adjustments than my beds clock and because the radio in my Toyota might be tricky to get into the house all right little bit of static here uh oh there it is it's working it's actually [Music] working [Music] [Applause] that is so cool this is something I've only ever read about before or seen in other people's videos it's really cool to have this actually running on my desk here with real Hardware that is awesome there is some heavy interference but that might be the monster power supply in this thing but uh yeah you can clearly hear the tones and you can sort of Make Out full on the hill in places it's running a little fast and there's some notes that I don't recognize but uh yeah I I didn't put in I think the correct Tempo so it might be just sort of off a little bit but man yeah that is just you know 50 years after this was first demonstrated here it is on my desk this is the kind of thing that brings history truly to life you can just imagine what it must have felt like to be sitting in the auditorium where they held The Homebrew Computer Club meetings and how the assembled hobbyists felt hearing music on a personal computer for the first time along with all the other firsts they were stumbling into with this new machine that hadn't even been possible to own a few years ago actually you don't have to imagine it really according to Steve The Homebrew Computer Club audience upon hearing this digital music demanded an encore wow what a truly unique and historic machine the alter is I'm so grateful to have one now okay so now to other business what am I doing with the remains of what was supposed to be my built from pieces Altera well as you may be aware the chassis that I bought to go with my revzero kit Parts comes from an alter 8800b TurnKey the outer cover obviously came from an earlier alt ha but it was exactly the same for the turnkey version so that doesn't really matter last year I picked up the alter TurnKey controller card which is crucial if you want to use this thing as an actual TurnKey machine and I think that that's my plan for now I'm going to just collect pieces and hopefully restore this bag of bones back to an alter 8800b TurnKey which is an interesting machine in its own right and yeah I know that presents a lot of the same problems as the original 8800 especially the front panel but the difference is I've actually seen various TurnKey components come up on eBay before in some quantity and since it's a less desirable version of the alter the prices are accordingly lower usually so there's some hope of getting it done all Al though it may be derailed if I come across another alter 8800b turn key on eBay that's complete and at a much cheaper price than all the parts individually would cost a purchase I'm not quite as enthusiastic about the turn key obviously as I am about the original alter so I can wait as long as required to get all those parts together I've actually had success with this strategy before I recently rebuilt a polymorphic poly 88 which I originally acquired as an empty case this way and I'm currently doing something similar with a poly 88 83 even if the buy it in pieces method isn't cheaper than actually buying a complete unit it sometimes allows you to kind of spread out the cost a little bit so yeah that's kind of the plan in terms of future plans for this alterate 800 I will probably try and find a serial board for it so I can hook it up to my teletype and experience the earliest versions of Microsoft I mean Al teror basic but that'll be another day I don't think I'm going to do too much else to this machine I mean I could if I find the original part uh restore the original back plane and power supply to make it somewhat official again but uh I'm not really too worried about that it's more just having the thing that looks like the thing and has the same functionality and the Heart of it is still a real alter that's all that really matters anyway thanks so much for watching this video if you like what you've seen smash that like button if not hit the dislike button I can handle it I promise and if you're really enthusiastic please consider subscribing or becoming a patron patrons receive early versions of my videos as well as exclusive behind the-scenes content and will receive other stuff I dream up as I go anyway thanks so much for watching and we'll see you again very [Music] soon

Channel: Tech Time Traveller

Views: 83,386

Keywords: mits, altair, 8800, intel, 8080, first computer, personal computer, computer history, programming, computer music, the 8-bit guy, Adrian's digital basement, retrotechnology

Id: CZgD_bvPm0k

Length: 49min 27sec (2967 seconds)

Published: Sun Dec 17 2023