How the Commodore REU Works

[@matthewray6008]

My uncle ran a computer store in the 80s and I just texted him to see if he knew how much REUs went for. He has always been a Commodore fan (he even has a tattoo of the logo). He said that he can try and track down a price sheet from back then but he's pretty sure they were MSRP for 299 but most shops would price them at MAP which was 199.

[@DryPaperHammerBro]

MAP?

[@Jody_VE5SAR]

MAP - minimum advertised price

[@James_Moton]

@@Jody_VE5SAR A store can't advertise a product for lower than the MAP (minimum advertised price) without risking penalties for the manufacturer. If a store wants to sell a product for $189, but the MAP is $199, then they would have to show the customers the full MAP of $199 but provide a $10-off coupon for the purchase of the unit on request.

[@pd1jdw630]

Gsus! It was more expensive the the commodore itself.

[@BastetFurry]

@@pd1jdw630 well, RAM wasn't cheap back then.

[@freddaniali]

David, I bought mine from Best Products for $149.99. I do remember that the price had no catalog listing and when I asked them why they said that the price of dram was very volatile at the time. And, when they had to look it up it was listed with the jewelry department since it had to be where their program allowed them to easily modify the price.

[@TheMasonX23]

That's really neat, thanks for sharing! Not only did you know the price, but I love that you knew why it's unlisted and even the tidbit about the way their pricing system worked haha.

[@alexanderthomas2660]

LOL @ jewelry! Imagine wearing 2 of these as earrings…

[@highpath4776]

@@alexanderthomas2660 Well RAM Chips often are

[@ut4321]

Fascinating, thanks for this comment! I remember when the US Congress punished China for dumping DRAM and the supply dried up. I was outside the back door of Softwarehouse in Dallas (in the rain, no less) begging for a tube of DIP DRAM to put in a system to ship the next day. Crazy times. "Supply chain issues" aren't a new thing!

[@geekwithsocialskills]

The 32K EPROM socket can be used to add GEOS onboard to the REU for instant loading of the base GEOS application.

[@geekwithsocialskills]

@@8BitNaptime I believe it does have priority. I no longer have a REU to confirm.

[@RacerX-]

Great Video. I can help with the price. The REU listed for $149 in the USA when it came out but I got mine on sale at Toys R Us for either $109 or $129. I do know that later on they were selling them for $99 and that is when we picked up a second unit for our BBS. I still own my 1764 and the PSU is still in use on my 64C.

[@BrianMelancon]

I'm pretty sure I picked mine up for around $100. I was a poor college student at the time. I definitely would not have spent more than that. I used it along with CNet BBS. CNet used this trick of overwriting specified sections of running code with different code loaded from disk. This allowed the size of the program to be much larger than available RAM. By copying the program disk to the REU, then running it from there, not only did it run much faster, I had the entire floppy disk space available for saving the data from the BBS.

[@RacerX-]

@@BrianMelancon Oh that is cool, I remember CNet but never used it. I ran a Color64 BBS and the REU used it as basically a drive and it installed all the BBS overlays to it so that it would not have to load them from disk. Overlays were basically games and mods for the BBS. The bootup took some time and required several disk swaps and Commodore's own software fast loader. I still have all those files but can't remember how to boot it. haha. One of these days I will try it again. Yeah $100-129 for the REU at the time for a computer that was only $129 was a large investment for a kid just out of HS as I was. haha.

[@robertleeluben]

@@RacerX- What was the name of your BBS?

[@RacerX-]

@@robertleeluben City Limits BBS.

[@robertleeluben]

@@RacerX- it sounds familiar, I was all over Miami area BBSs and did a lot of CG graphics as Creeping Death.

[@8_Bit]

Several of the later Infocom games shipped with REU support which allowed pre-loading of data into RAM, greatly speeding up the time it took to process your turns.

[@8_Bit]

@@RockProductionsYT I'm from the future.

[@Rhyean2004]

@@RockProductionsYT unlisted video available to patreon subscribers

[@Orincaby]

@@RockProductionsYT people pay to see his stuff early

[@lordevyl8317]

The new port of New Rally-X also has an REU version on the developer's itch page

[@dennisneo1608]

@@8_Bit Yet, you love the past?

[@Toonrick12]

Sonic is actually a port of the already existing 8-bit version for the Sega Master System/Game Gear. That being said, it's a near perfect port of it, and it even runs a bit better than the original version!

[@JustWasted3HoursHere]

Next thing you know you're going to tell us that the Super Mario Brothers game was also available on some other system before the C64! ;) Or were you just being cheeky with your comment? If so, well done. You got me!

[@wybuchowyukomendant]

@@JustWasted3HoursHere There were no systems before C64 - myths, legends and fake news!

[@TheGuyWhoIsSitting]

@Brandon Taylor SEGA has selective caring. It seems like most of the time they'll let Sonic stuff slide, but SEGA is more protective of their other IPs in terms of fan works. I remember they were issuing take down notices of people merely uploading Saturn gameplay and I've seen groups receive C&Ds for fan games like the Streets of Rage remake and a few other things.

[@lasskinn474]

@@JustWasted3HoursHere port of the gameplay and gfx, rather than demake of the megadrive version

[@SergeantMajorH]

I have sonic already on 2 disks waiting to play, but cannot find an reu.

[@TheSulross]

Sonic the Hedgehog port to C64 was a real shot in the arm to 8-bit retro game development world as it so viscerally made very clear what the REU brings to the table - exciting

[@satan3959]

Agreed. Although more native games for the SuperCPU would be nice too

[@ponocni1]

From what i saw on screen it was most likely Master system port.

[@satan3959]

@@ponocni1 Even the developers say as much

[@sonicthehedgehog23145]

@@ponocni1 i feel like the genesis sonic 2 could be ported to the amiga ....if you really tried

[@ponocni1]

@@sonicthehedgehog23145 I see no reason why it could not. Only what might be limiting factor are sprites and onscreen color pallete, maybe memory. Also question is, what amiga? There are multiple ones with some being much more powerful.

[@mikeprice2311]

I love how they even recreated 8-bit Sonic 1s broken demo. That's true dedication to the source material.

[@milk-it]

The C64 was my first computer. I'm always blow away by how much good programmers could squeeze out of that thing! The quick dive into assembly instructions and clock cycles was really interesting. I'd love to see more of that.

[@kaseyboles30]

I had one of those. I even had it all wired up with extra sockets and the glue logic (74series ftw) to make it a two megabyte reu, just at 15 I never came up with the money for the actual ram chips. There was also an update to software to properly use all that ram. This was more ram than pc-xt's of the time.

[@HelloKittyFanMan.]

Yes, it's so interesting how there's now quite the cult following of the C64 that can finally afford to use these super accessories that we wish we could have had just as easily some 4 decades ago! And with people developing modern solutions for old machines, like being able to run flash storage on these computers, this is really a magical era for nostalgia, isn't it?

[@carlangelo653]

Not just nostalgia, it's quite amazing how even people my age (born late 90s) can still use and experience these machines. It's because of the documentation and preservation that the community has done. And as someone who is interested in retro tech I'm very thanful for it.

[@HelloKittyFanMan.]

@@carlangelo653: Nice, yep!

[@sammymcfone8281]

Yeah i look back with resentment. Im like "oh you have an 040 cpu... Thats cute.. i just threw away a pentium 233 mhz chip cos its taking up space.." :)

[@sammymcfone8281]

Too many years running workbench on 2 megs and no mmu i suppose. Lol

[@peaklettuce]

Back in the early 90s, I ran a CNet BBS off a REU using it as a ram disk on a C128 in 64 mode with two 1581s. Had the BBS menus and doors stored on the REU and the message base on a 1581. Think I only had a 2400baud modem but even with that the REU made a noticeable performance boost for users. Within a few years, moved on to a A500.

[@AIM54A]

Good times Don. I ran a BBS from 86 to 89 on a Apple IIC with a external 3.5 drive and I think it was 512K memory upgrade using a 2400 baud modem.

[@ScottMcGlynn]

I was wondering anyone would mention this use case. I ran my 1750 clone on a 128 with New Image BBS for a few years in college. It took forever to power it up and copy all the modules into the REU but it ran so smoothly once it was up.

[@jeredhunter7726]

I think your first sentence might be the most beautifully retro thing I’ve ever heard.

[@SeeJayPlayGames]

you ran a BBS on an A500? Blasphemy. I had a friend who had pretty much every major "A" computer except Apple - Amiga 500, Atari 520ST, Atari 800XL... and he ran the BBS on the Atari 8-bit then later a PC. He never used the Amiga for running the BBS. Mostly calling them. And playing games.

[@boardsort]

Same here Don. I ran a Cnet bbs with Empire and a few other overlay programs loaded into what we at the time called a "Rampack". It made a big difference in game play as Empire was a series of overlays that needed to be loaded in sequence with each game event. Good times.

[@brendonburgin5250]

My mother entered my brother and I in a draw in New Zealand, he ended up winning 1st prize which was a commodore 16. Mum had stressed to both of us if one happened to win then the prize was for the two of us so we were stoked. We had that computer for approx 6 months when to our surprise Dad went and upgraded to the commodore 64 with the tape deck, floppy disk drive & dot matrix printer. Along with all that we got some games on cassette and cartridge, I remember really liking 'Who Dares Wins' on cassette and 'Lode Runner' on cartridge. We did eventually get some games on floppy disk and they loaded fairly quickly. We had a lot of fun with this setup as it kept us entertained for hours.

[@danielstickney2400]

My experience with the 1764 REU was discovering that my RAM disk was not as slick an idea as I thought when my C64 crashed and I lost the term paper i was working on at 2:00 AM in the morning on the last day of the semester. The old and dying refrigerator drew enormous current when it kicked on and my landlord's brother-in-law wiring job wasn't up to the task of supplying it and the rest of the house. Fortunately I only lost the bibliography but man it was a pain. Save early and Save often has been my motto ever since.

[@letthetunesflow]

Really neat stuff! Not going to lie, I really miss 8-Bit Keys uploads… I’m sure you are extremely busy with all you projects, but I’d love to see you messing around on old keyboards again sometime. Any chance of that in the future? Or have you moved on from doing that for the foreseeable future? Regardless thanks for all the amazing things you share with us all! I really did enjoy seeing you clean up an old keyboard and then writing some fun music for it!

[@ckjuicyj82]

I too enjoy and would like to see more 8-bit keys!

[@chester8420]

8-bit-keys has always been your best channel. Your weapons channel is for sure #2!!!

[@secretjazz93]

"how 8 bit music was created" was the reason I subscribed, before he was even called the 8 bit guy. I've never been disappointed by a single video, but I sure hope he'll do another 8 bit keys video in the future, those were the BEST 🤟🤟🤟

[@sailcat662]

I like that you have actual good sound production levels. Love you show!

[@pixeldiscoveries]

Love these behind-the-scenes looks at old technology, bravo 8-bit guy!

[@bitterlemonboy]

bravo vince

[@dreadpiratesidebeard9471]

What is going on with KZbin? An 8 Bit Guy video should be over 100k easily after 12 hours. Especially a classic vintage tech piece like this! I didn't even get a notification despite choosing that setting.

[@noknowledgeiseverwasted]

BTW, your opening theme song makes me happy every single time I hear it. It's everything I wish my memories of the 80s were actually like.

[@PostProteusKitten]

I came here to say this. I've been watching for years and the theme still slaps.

[@calvinhenio4456]

Same. I love it. 😁

[@bozimmerman]

Great video as usual. Just wanted to say that, after the fall of CMD, we were in an REU desert for ages! The 1541 Ultimate II was some relief, but it was very expensive for a long time, and might still be considered a bit of overkill. I think we are finally going to start seeing actual stand-alone REU clones in the next few years.

[@thecorruptedbit5585]

Couldn't you use a Turbo Chameleon? (it's really overkill, but still)

[@RacerX-]

Yep for sure. I beta tested an REU compatible project that was 100% compatible, that I could see. I think he released it as open source but not sure it was actually finished. The prototype that I have is large but also had things like VGA out, RTC and something else. He streamlined it to just an REU but I have not seen that one yet.

[@RacerX-]

@@thecorruptedbit5585 yes you could as it also has REU built-in. But like you said if you just want REU it is overkill. A cheap alternative is in the works.

[@mirage809]

That Sonic port is insane! It looks and sounds a lot like the Master System/Game Gear version. Something that is simply incredible with how limited the Commodore hardware was for that sorta stuff. It's also really neat to see every version Petscii Robots get updated to use every obscure and weird expansion out there.

[@satan3959]

That's because it's a direct source code conversion of the Master System port.

[@fixitalex]

Yea! RAM those days was something you never get enough

[@rodhernandez4134]

The C64 version had the ability to add more RAM to it. There was a jumper that you had to either cut or solder together, I forget which. And you also had to add RAM chips to the empty spots. They had two rows of RAM chips. One was populated and the other was not.

[@Torbjorn.Lindgren]

AFAIK all versions uses the same two circuit board (DIP/old vs PLCC/new), on the board there's a trace that controls whether it has 64kbit or 256kbit memory chips, and another that controls whether it has one or two banks. From what I can tell CBM never bothered making a 128kB variant. Many sources say there's an extra resistor (R4) on the two C128 models and that this is required due to subtle differences in the C128 cartridge connector to avoid "stability issues". And that as a result you should remove R4 on the REU before using it on a C64, and add it to the REU to run on C128 (or I guess, install a switch if you move it back and forth).

[@richardknezevic7371]

that was the amgia 500

[@drtidrow]

IIRC, I got a 1764 expander for my C64, and later added a second bank of RAM chips to bring it up to 512k. GEOS could use the expander as a virtual disk, and was pretty quick as a result.

[@TheGuyThatEveryoneIgnores]

4:46 The branch instruction takes 3 clock cycles if the branch is taken, 2 clock cycles if it is not. The branch is taken for every iteration of the loop except the last. Also, if the addition of the X register to the addresses indicated in the LDA, X or STA, X instructions crosses a page boundary (where each page of memory is 256 bytes), those instructions will take an extra clock cycle to execute.

[@ExcalibursZone]

I had a 1750 back in the day. I used it with my copy of C-NET/64 where a lot of the BBS software would be copied on startup. It made the experience a lot faster and allowed for the floppy drives to be used for file transfer and message storage. I think I'd gotten mine for around $350 at the time, but I can't remember exactly.

[@electronerd]

I don't know why, but I absolutely love this channel's intro music

[@wizkid723]

If you were looking for avg price of the REO, check Internet Archive (Run Magazine, Issues 80+ which is 1991 time frame) - Issue 85 - May 1991 - From Software Hut In PA - REU1750 - $129, 1700- $49, 1764-$109. Many of the old magazines had stores advertising items.

[@8_Bit]

Those were heavily discounted prices by 1991, being sold as clearance. You'd need to find magazines from around 1986-1987 to find the original prices.

[@Okurka.]

@@8_Bit The 1764 cost $149 in 1987.

[@vadermasktruth]

I'm a 51 year old dude, probably your age also. I love going back and rewatching your older videos! Four, five, six years ago even. So much to learn & relearn, this is one of the great things to use KZbin for! Lots of negative things about YT, and although I love Rumble & Bitchute, YT still "works" the best with a plethora of information!

[@c128stuff]

The ozmoo zcode interpreter supports the reu, so all zcode based games can now use it to preload data, and in the upcoming release, for a scrollback buffer.

[@DonaldWMeyers-dwm]

I used the 512k REU on my C-4, putting the GEOS programs I was running there which made it highly responsive. I thought that was the greatest thing, and now I have multi-terrabyte disks sitting on my desk.

[@Okurka.]

Mine are terabyte disks.

[@kaseyboles30]

Using it as a ram disk was perfect for running a bbs, color64 bbs to be specific. Especially if you had lots of kids for it.

[@slimebuck]

i enjoy the production value of your videos. sound, video and editing is all 10 / 10.

[@ClassOf90Retro]

Another use of the REU that is difficult to appreciate these days is for a larger backbuffer in compatible terminal programs for bulletin board systems. Not everyone can keep up with a blazing 2400 baud modem so being able to scroll back and read the buffer was useful. The bigger the better.

[@senilyDeluxe]

There are a few more uses for the REU, not just for Demos. (but all of these require 16MB REUs) There's the Nuvie video file format which allows you to watch videos in 320x200 with 4 bits per pixel (yes that's impossible on paper) Then there's the Bad Reception TV which is another video file format that allows you to watch videos in... character definition, which means really crappy video quality, BUT it has wave sound instead of chiptune so you get the original soundtrack to the video. Also they last a lot longer, around 3-4 minutes as opposed to around 1 minute for the Nuvie. And then I have a friend who has developed the BreadAmp (think WinAmp) for the Commodore 64, it plays better-than-AM-radio-quality (15kHz mono) wave sounds and fits around 10-12 minutes on a 16MB REU. It does support stereo sound but you have to use two SIDs. He's currently working on another video file format that uses KoalaPaint images, the quality is slightly worse than Nuvies but a hundred times better than BRTV and it retains the wave sound.

[@mmoore321]

I had one for my C128. Used it mostly as a RAM Disk for GEOS. Made it lightning fast. Just had to remember to save any files back to disk.

[@Keatosis_Quohotos]

I absolutely never tire of seeing petscii robots on this channel. I think it's fascinating to see it evolve, and it really sets this channel apart because basically every device you review has a special petscii port that specifically shows off its features. It's not something you can really get anywhere else on KZbin

[@Brunosky_Inc]

Once you brought up the surprising capabilities of this device, I was hoping you'd mention that you ported Petscii Robots to work on it. Great to see that! The jump in visual quality is impressive considering this is possible by just connecting a peripheral to a regular C64.

[@NuntiusLegis]

I think it's a strange concept to remove PETSCII out of PETSCII Robots.

[@GrymWorks-A.I.]

My first foray into chip-stacking was with a 1764 REU. Cut the power trace on the edge connector and gave it it's own power supp;y with a battery back up! Ran an unlisted Color64 BBS for a few off that and a CMD HD

[@Joeybamillion72]

I always love seeing your videos, I'm not the brightest person but I love learning what you have to offer. We are so spoiled of today's technology but I highly invested in all your videos. Keep them coming!!

[@bubbadmatt8124]

Just curious, ever thought of going on a small tour to give technical seminars devoted to discussing techniques for vintage tech restoration? If you, LGR, techmoan, Tech Tangents, and your brother were to hold a conference panel I'm sure there'd be a great turnout.

[@diwest1737]

It was great seeing you at Game Fest in Austin. I’m glad the copy of Sonic I gave you was put to good use. Great video as always.

[@johnmijo]

Thanks David, I completely forget that we supported the REU in Maverick. Thanks for showing this device off as it was a somewhat niche product probably due to pricing.

[@Tahngarthor]

I for one remember seeing "$CALL" and similar in sales flyers throughout the 90s and it really annoyed me. Sure, sometimes the price might be fluctuating, but I generally took not showing the price to mean "it's way too expensive / our price isn't the cheapest."

[@seretkeena]

When I was little, we bought a brand new C128 system with a 1084s monitor and the 1760 REU. We used it primarily for GEOS in 128 mode, and mostly to copy applications from the various disks into the REU at runtime so it was faster and easier to run a bunch of things at any given time. Of course, we had to reload it every time we rebooted the 128, but it was at a time when you never expected instant gratification. You'd sit down, boot up and load GEOS, then after it was loaded, pop in our prepared applications disks and copy them into the REU before we started doing anything. I remember trying to use it in C64 mode and never really understanding why it didn't do anything but that was my pre-teen self having a very rudimentary understanding of computers and what they were capable of. I do remember that the cost of our 128 system including a printer was somewhere near a thousand dollars at the time, and this was somewhere between the late 80's and early 90's. I want to say somewhere around 88 or 89. It's been a long time, but I vaguely remember the REU cost somewhere between $50 and $100 depending. Most people didn't have them, I knew more people that ran dual disk drives than had an REU at the time. Then again, we bought ours on base, so it's possible there was some kind of special military discount so my prices may be faulty. Seeing some others mentioning around $200 wasn't out of the question, it would have depended on how and where you got it, too.

[@charlesrovira5707]

@5:35 I love your t-shirt. Where did you ever find it? I saw the film/documentary years ago.

[@kjakobsen]

The video clips, this expansion enabled was impressive. The Dallas intro sequence for instance.

[@moistandwhite2636]

I can’t believe I’m exited to learn about obsolete electronics I’ve never heard of

[@Fraterchaoraterchaos]

I had one of the C64 units with 256K... I added my own 256K bytes of RAM to it for about 1/10th the cost of buying the bigger unit. Just took a little soldering. later one, I bought a third part CMD RAMLink drive, which was a similar device, except that it had it's own power supply, plus battery back up, and it used industry standard SIMMs of 1,2 or 4 MegaBytes. So, I had a C64 computer with 4.5 megabytes of non-volatile RAM Disk (almost like having a hard drive, as long as the power didn't go off for too long) Ran GEOS OS on it, which was awesome because could boot into GEOS as quickly as a normal C64 could boot to basic. You should try to find a RAMLink if possible, they were really great devices

[@fyreantz2555]

The fact that you know so much about this stuff is simply astounding. Thanks for sharing!

[@Okurka.]

This isn't rocket surgery.

[@UltimateTechHub]

I remember programing the C64 when I was 10 years old! It was amazing and so ahead of its time. Great video!!

[@EvoGeo]

I literally just used the globe demo to test a fix I did on my old 1541 this afternoon! Wow, what a weird world!

[@ricky_pigeon]

12:49 Sonic ending his life.

[@rpdee7344]

8/5/22 Great review, I still own my Commodore 128 with the 1750 ram expander, 5 1/4 floppy drive, 1581 3 1/2" hard floppy drive, and a C=> monitor. I ended up buying my ram expander from someone on Q-link. and your right it was quite expensive, but I was a bigger user of the various GEOS programs making my computer very useable as a desktop along with my HP Deskjet 500 where I could DL a printer drive off of Q-link. All that you said was true about speeding up things when using the expander, plus I had a jiffy Dos chip installed to speed up the booting. Nice to see that there still are users out there still supporting C=> in 2022. The fact that the 128 was a 3-in-one computer where I used both the 64 modes and 128 modes spent a lot of fun time and useful hours while never turning the computer off without any power or heating problems for years.

[@MrCenturion13]

I bought an expansion kit for my 1750. Bumped it up to 1024k - could have pushed it to 2 megs, but there were rumors that this was hard on the REU's MMU chip and it would sometimes fail. The kit had a daughter board, a lot of memory chips that had to be soldered in piggyback on the stock chips. 15ns chips! There was an article in RUN magazine that talked about it in detail. I still have it!

[@hssreddragon3924]

Locally we used these REU's to power our BBS software and load the entire BBS into the REU so it would require less (slower) disk access. We also had a local modder who would upgrade smaller memory units to 512k to save on costs or availability where possible. Very handy units!

[@johnandrews2167]

I still have one of these for my C128D, and it still works! Made things work much more efficiently.

[@BOBXFILES2374a]

I had a Commodore, but never heard of the REU. What a brick! No, TWO bricks to power up! Happy computing!

[@maxwellhansen522]

Glad to see a video about the REU, have had one lying around for awhile and have been interested in them for a long time.

[@pault151]

At the San Francisco Commodore Show, must have been about 1986 (?) there was a C-128 demo running off of a REU. It was a near-copy of the Amiga Boing! demo. It was very impressive on its face, but it wasn't randomly hitting different places, it was just looping a couple of cycles of back and forth. Of course, the Amiga next to it was doing the Boing! while using about 5% CPU and having draggable screens, while the 128 was running all out just to show it. Still, the marvel is not that the bear dances well, but that the bear dances at all.

[@NeverlandSystemZor]

I LOVE that someone made a Sonic the Hedgehog port to the C64! That is one of my favorite retro games. I remember the awe hearing my brand new Genesis sing "SEEEEGA" the first time I powered it on...

[@SockyNoob]

Great video, crazy how they got around system limitations back then

[@slamtilt01]

Back in the day I remember seeing computer peripherals advertised. It would amaze me that their cost would often amount to way more than the computer. It doesn’t surprise me now that your ad showed a”Call me” in the price Column. Most items like that back then, needed an explanation of their use.

[@TheOriginalJphyper]

Neat! Two of the three channels I've rung the notification bell for have uploaded on the same day!

[@w3rdup91]

I remember I had a REU for my Commodore 64 specifically for running the bbs software Color64. Color64 had modules that needed to be loaded up every time a user went to a different section. Without a REU the modules would have to load off the drive which would take time. With the REU no loading time as it was much faster. I remember some bbs's that ran color64 used hard drives for the C64 at the time and didn't need the REU since the drives were fast enough to load the modules. Good memories and good times!

[@TheOriginalNCDV]

Can't believe I still hadn't bought a copy of PETSCII Robots! I'm glad I watched this video, just ordered the REU combo 😀

[@jameslewis2635]

I would have thought that one of the main things that these expansions would be good for would be in terms of running GEOS on the C64. In fact, I suspect that ROM point could well have been intended for GEOS to be pre-loaded into the ROM making for very fast boot times and having more memory available in order to run programs on top of GEOS.

[@XalphYT]

I was a heavy user of GEOS back in the day, and indeed, the 1750 hooked up to a Commodore 128 made GEOS lightning fast. That alone was reason to get one.

[@Curt_Sampson]

Actually that BNE will usually be _three_ cycles, not two. BNE is two cycles when the branch is _not_ taken and either three or four cycles when it is taken, depending on if it needs to cross a (256 byte) page boundary. In a loop copying several pages of bytes it will of course be taken about 255 times as often as it's not taken, and there will also be a bit of extra overhead for setting up the loop for the next 256 bytes to copy. That's a minor quibble, though. Overall, nice job on explaining (for those not familiar with this stuff) why DMA was so much faster than programmed I/O!

[@AmyraCarter]

Ah, a seemingly competent port of the Sega SC-3000/Master System iteration of Sonic the Hedgehog. Nice. very nice.

[@five-toedslothbear4051]

Thanks for the video! I’m old enough that I could’ve owned a Commodore computer, but I just never did. I love the technology of old computer systems, and you do a great job of explaining it. Also, love the shirt! Classic poem!

[@nucflashevent]

6:20 "not sure how useful since it will lose its contents at poweroff" -- puts new meaning to the age old wisdom of keep good backups :P

[@SidneyCritic]

Is it possible to level the volumes in different scenes because it goes soft loud soft, etc. I have damaged hearing so I really notice volume changes, ie, the loud bits hurt.

[@SteveGuidi]

I owned a 1764 for my C64c, and purchased it new in the early 90s. Unfortunately, I don't recall the price but do remember that this particular purchase (in Toronto Canada) did not come with a power supply. I don't know if Commodore had an REU SKU that didn't come with the power supply, or if the store just removed them from the package; the C=-branded box was definitely small enough to hold just the REU, disk, and documentation. I didn't have any power issues running GEOS or other software with the REU, but I also did have an early-90s power supply straight from Commodore Canada as its predecessor failed early in its life.

[@rbnlenin]

Hiya David, awesome explanations for the technical aspects. Working on learning reversing now, and it's always fascinating to see that, while we may have more bells and whistles on modern systems, it's still fundamentally the same as back in the 80s.

[@MrMegaManFan]

“Let’s go back to 1985 and the introduction of the Commodore 128.” Oh I wish! But happily I still have mine from back then.

[@davidnicholson4136]

Back in the day I had a 256K REU for my C=128. A friend in our local Commodore Computer Club piggy-backed some RAM chips onto the existing RAM chips and (with some simple, but clever wiring) converted it to a 512K unit just to demonstrate that it was possible. I don't have my Commodore stuff anymore (sigh) and my friend has passed away, so I can't give you specific specifications for the conversion, but I do remember that it was a fairly simple hack when he showed me how it's done.

[@nucflashevent]

It's been my experience a lot of "expand whatever up to" was usually a euphemism for "we don't forbid it" :p

[@thecorruptedbit5585]

Very glad to have gotten one of these (and the super power supply for the c64) as part of a lot before the craziness that is C64 Sonic drove up the prices. Also very glad that I learned a bit about 6502 asm so that I could understand the bit about the CPU cycles! Awesome video as always

[@seamusoblainn]

Petscii Robots is on so many systems now, it's almost like benchmarking software for retro systems 😁

[@aliensporebomb]

I remember owning this with the C-128 - we brought the memory expansions to a local guy who added extra chips who could turn the 128 model to 512 etc. As I recall the higher one could be expanded to 768. It's been years since I thought about this unit - I wonder who ended up with it?

[@tweakpc]

We had an expansion card for the C64, my brother got this one, the seller has pushed him to buy withit. Actually, my brother wanted to buy an Amiga 500 then. The seller has probably cheated him quite bit. But to take him in protection he was still young at the time. I can no longer say the price but the expansion was expensive and seemed pretty useless to me when I used the C64 and got it years later. Now I know why, I never saw the utility disk. I wonder if my brother got it back then, because I still had the complete disk box many years later. thank you for the video after all these years you have solved a mystery . BR Thomas

[@micione1975]

The only reason that could push me to buy a REU back in the 80's was an arcade port of dragons lair or space ace. Thank you 8 bit guy for this video.

[@wesjb94]

I love this channel. I won't pretend to understand lots of what's going on but I am learning!

[@CrazySpence]

As soon as I heard the slightest mention of Sonic before it became widely known I bought my REU off Ebay for about half of what they were going for a month later. It's a neat device and it opened up the ability to play Sams Journey on NTSC which is an absolutely delightful game. What people seem to be doing more now though is just using larger carts to feed their games. A Pig Quest which is hopefully out this year is all bitmap GFX and uses a big cart format. Lykia is a 1MB cart game which is a lot of data in 8bit terms. But I do think between REU and large size carts we are going to see some absolutely stunning titles in the next couple years.

[@tonybossaller4074]

Wow. So much to add. I own all three models 1700/1764/1750 and one of them was modified to 2Megs by literally stacking chips. I can try to get some pics. For me, why I have these is… I ran a Color64 BBS which could use the ram disk as fast storage to swap modules (messages, xfers, games, etc) superfast versus floppies. Before the REU, the Lt. Kernal hard drive (with parallel access) was the best option. Eventually Color128 was released which could utilize 80-column mode, ANSI, both 64k ram banks (which solved a major issue with ColorBBS) as well as 2mhz mode (and being able to go up to 9600bps.) Burst mode however meant that even a 1571 was pretty fast to load. My BBS used an REU for actual system files with a backup stored on a RamLink (CMD) which had a battery backup. But I’ll dig those out and show them off. The 2Meg REU I have still has the original shop that did the mod listed. I believe Transactor magazine showed how to accomplish that (so that might be a fun side topic/project). I believe the CMD XL actually uses the REC chip from post-collapse Commodore to function and also why so few of them existed. I do wish someone would develop a modern REU using modern chips and just transplant the REC in. It’d save power but also be able to go beyond 2Megs. See the 2Megs was accomplished by switching banks in. I believe 2Meg was the limit of the existing bank select byte (using all 8 bits) but you COULD in theory add another byte in another location to swap in even more memory but as little software could address, I don’t think many did though I did see the emulator you had did reference a 16meg one, which ironically is the max on the RamLink. Thanks for posting!

[@redthorne2836]

I love learning about all the stuff I didn't know existed for the 64, as I was just a smidge too young to understand it all. I hope to some day find a working unit and start my retro-collection with it, followed by an A500.

[@Okurka.]

Great research(!) The price of the 1764 is listed on Page 48 of Compute! Gazette Issue 63, on page 48 of Run Issue 43 (1987-07) and on page 37 of Run Issue 75 (1990-03).

[@ScrapKing73]

And? My Compute!’s Gazettes and Run magazines are boxed away, please put us out of our misery and tell us what the prices were! :-)

[@Okurka.]

@@ScrapKing73 There's a thing called PDF now.

[@bozimmerman]

@@ScrapKing73 Found it. :) $109 for the 1700, and $117 for the 1764. (Only $8 more for that big old power supply and double the ram? Really?).

[@Okurka.]

@@bozimmerman Those are discounted prices from 1990 or so.

[@lordevyl8317]

He's looking for the ORIGINAL release price, NOT discounted prices

[@retroandgaming]

Run Magazine issue 47 - November 1987 page 50: 1700, 1750 and 1764 REU carts for $119,95, $199,95 and $149 respectively. Starting at page 45 in the same magazine "The tale of the RAM and the Mouse" is a good read.

[@sambrown8636]

Brilliant video, thanks. It must take ages to do all the graphics but they explain everything so well! Really enjoyed that. :)

[@rxblackpill]

You seriously make the most entertaining videos Dave! I one day hope to have enough spare time to make something for the C64, VIC or Amiga that could stand up to the best!

[@andresbravo2003]

9:26 Oh Wait, it included Sonic in this video! Nice work David!

[@michaelhoule2134]

I was computer monitor in grade 5/1987. I had to leave class 5 minutes early and boot up (turn on) the C64's and load them up. LOAD"$",: return is still burnt into my brain. I'm 45 now but I'll never forget that boot up sequence. I was always interested in computers but we never had a home computer until the late 90's, 96/97 I think.

[@Niarbeht]

Every time you play a version of PETSCII Robots, I just get reminded of Ultima 6.

[@flybyw1re123]

I always love when the 8 bit guy uploads. his videos are always interesting.

[@kjrehberg]

Reminds me of my TRS-80 Color Computer 3 512k RAM expansion which also used bank-switching, except that unit went inside the CoCo 3's case and generated a ton of heat. It was also one of the first victims of a DRAM shortage in those years, inflating its cost by 200%.

[@amirtavakol8256]

Dear David, Thank you for sharing useful information about Reu. Unfortunately I don't have real hardware, but thankfully vice emulator give us this chance to have fun moments with reu specially watching nuvie videos

[@vcv6560]

Of that "call for price" mentioned..The other thing to remember about the time the DRAM shortage from the terrifs on imported 256K chips, 88-89 particularly. I ran into this buying cards for my Amiga 2000 2M boards went from $399 to $499 to finally being sold unpopulated. In Silicon Valley there were breakins at stores and warehouses looking for parts.

[@hellocollegejason198]

Always great to learn from a new video

[@jafizzle95]

The soundtrack in this video is so good, I had to go listen to the whole thing on Spotify after finishing this video. It's the Attack of the PETSCII Robots soundtrack by Anders Enger Jensen for anyone curious.

[@RedMorgan79]

David I hope you and yours are doing ok in all the wet weather in your area. My family is thinking about you. I hope your recently-repaired home stays as dry and watertight as a drum. -Morgan

[@optigrabbingit]

I found an ad from Dataworld in the Knoxville News-Sentinel from July 13, 1986 that has the 1750 RAM Expansion priced at $245.00.

[@FeedingDragon]

Many of the later Infocom games and some re-releases would use the REU. The initial load time was longer, but after that, it did everything (except game saves,) from the REU instead of disk.