|
300 bytes/s, what a slowpoke. Even Atari's 1050 disk drive was better. With 19200 kb/s you at least got something between 1024 bytes/s and 2048 bytes/s. In both cases the serial connection was the bottleneck. Cheap, but not very fast. But why should it be? Those computers never had more than 64k memory to fill.
Fast forward to today. While the idea of having something like a single board computer to control the drive, manage the file system and data transfer from and to the main computer is still ok, we might get access to slightly more data and need better transfer rates.
Mechanical drives are out. Why not use a Compact Flash card as a SSD? Accessing it is extremely simple. You just have to map its 8 registers as I/O ports and you get access to gigabytes of storage. An 8 bit mode is also available, so there will be no waste of half of the memory space or awkward 8/16 bit conversion.
How fast will that be? At 6 MHz, my little CDP1802 processor can shovel about 37500 bytes/s and, since it's not a mechanical drive, the CF card can easily keep up with that. If the processor could fill its normal 64k in less than two seconds. Not bad for an 8 bit computer, but still slow if I want to use my unmodest 16 megabyte memory expansion.
Then there is the question, what file system I should use. Do you think that FAT32 is too much for an 8 bit computer?
And there is also still the question, what sort of connection to the main computer to use to get those bytes transferred fast enough. Serial? 200 kb/s with the old UARTs. More than 10 times faster than the old Atari floppies, bur still too slow. Parallel? We would end up at the processor's maximum again. 37500 bytes.
So that's it? Not quite. How about 250000 bytes per second plus freeing up the processor to do something better than just shoveling bytes around? The CDP1802 never stops executing instructions, not even for DMA. It just throws in an extra bus cycle with every instruction when DMA is requested. During that DMA cycle, it plays DMA controller and does the memory addressing itself. The other device just has to read or write the byte on the data bus at the right time. Maybe I can get this to work with the CF card's DMA mode and this also can be used to transfer data between two CDP1802s.
Not that the 1802 would be finished at 6 MHz. It's not even getting warm. 8 - 10 MHz are quite possible without any special effort. With using all tricks in the book (just look up how to overclock a modern processor in Wikipedia) I have heard that they can reach over 20 MHz. At that clock frequency it would reach over 833000 bytes/s in DMA mode and still be executing code. 16 bit computers that are 10 years ahead of the old CDP1802 would have a hard time to keep up.
I have lived with several Zen masters - all of them were cats.
His last invention was an evil Lasagna. It didn't kill anyone, and it actually tasted pretty good.
|
|
|
|
|
I do remember the ZX Spectrum tapes.
"In testa che avete, Signor di Ceprano?"
-- Rigoletto
|
|
|
|
|
I was once given the task of making a FAT-based backup system using one of those cassette drives and a VAX for the National Institute of Biological Standards and Controls during my second work placement at University.
It was brilliant, except when the tape stretched. Or snapped. Or snarled up. Or ... anything really.
It was useless, yes.
My code worked, but the hardware just wasn't up to it.
"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
"Common sense is so rare these days, it should be classified as a super power" - Random T-shirt
AntiTwitter: @DalekDave is now a follower!
|
|
|
|
|
OriginalGriff wrote: My code worked, but the hardware just wasn't up to it.
As usual! 
"In testa che avete, Signor di Ceprano?"
-- Rigoletto
|
|
|
|
|
I wish!
One of the hardest things in software to to say "this isn't going to work" and throw it away for a new approach. I'm getting better at that, but ... sometimes I still waste time on a brilliant idea trying to force it to do what it looked to be so brilliant at.
"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
"Common sense is so rare these days, it should be classified as a super power" - Random T-shirt
AntiTwitter: @DalekDave is now a follower!
|
|
|
|
|
I just had to do that with a project I'm working on. And I hate bringing that kind of thing to a client, but it's either that or throw good money after bad.
Real programmers use butterflies
|
|
|
|
|
One of the lessons I hammered into junior devs was to admit to and own a mistake/error early. We all make em the greatest fault is wasting effort continuing to build on them.
Never underestimate the power of human stupidity -
RAH
I'm old. I know stuff - JSOP
|
|
|
|
|
OriginalGriff wrote: except when the tape stretched. Or snapped. Or snarled up. Or ... anything really.
I still remember waiting breathless for the game loading (or not!).
"In testa che avete, Signor di Ceprano?"
-- Rigoletto
|
|
|
|
|
Quote:
F-16 autopilot flipped plane upside down whenever it crossed the equator.
Air New Zealand crash in Antartica when computer data error detected but crew was not informed.
Computer bug showed ghost train near Embarcadero station on San Francisco Muni.
Software bug caused F14 to fly off the end of an aircraft carrier into the North Sea.
F18 computer opened missile retention clamp, fired missile and re-closed clamp before missile had had enough time to move away from aircraft.
San Francisco BART doors opened while train was at full speed; control system's inter-station delay time was too short for TransBay Tunnel.
United Airlines 767 iced up because fuel-saving computer was over-efficient, causing engines to cool down too much on approach to Denver.
Mariner 1 launch failed due to period instead of comma in FORTRAN program DO statement (famously know to - The most expensive hyphen).
Computer error caused US naval vessel to open fire 180 degrees off target, in the direction of Mexican merchant ship.
Gemini V splashed down 100 miles off target when program used 360 degrees for Earth's rotation in 1 day, i.e. ignoring its movement around the Sun.
Vancouver Stock Exchange Index rose by 50% when 2 years of round-off errors in computer program were corrected.
Viking spacecraft had misaligned antenna due to faulty code patch.
F16 computer deadlocked, confusing left & right while plane was inverted.
180 degree heading error caused Soviet test missile to aim for Hamburg instead of the Arctic.
Autopilot error caused China Airlines 747 to stall near San Francisco.
Robot killed Japanese auto worker attempting to repair another robot.
AT&T software bug knocked out all long-distance phone service to Greece.
Shuttle laser experiment failed because computer data was in nautical miles instead of feet.
Woman killed daughter & tried suicide after computer incorrectly diagnosed incurable disease.
Computer error caused nuclear reactor in Florida to overheat.
KAL flight 007 strayed, shot down due to heading being mistyped into autopilot.
The British destroyer H.M.S. Sheffield was sunk in the Falkland Islands war. According to one report, the ship's radar warning systems were programmed to identify the Exocet missile as "friendly" because the British arsenal includes the Exocet's homing device and allowed the missile to reach its target, namely the Sheffield.
The Mars Climate Orbiter doesn't orbit
The Ping of Death. A lack of sanity checks and error handling in the IP fragmentation reassembly code makes it possible to crash a wide variety of operating systems by sending a malformed "ping" packet from anywhere on the internet. Most obviously affected are computers running Windows, which lock up and display the so-called "blue screen of death" when they receive these packets. But the attack also affects many Macintosh and Unix systems as well.
Morris Worm - The first internet worm infects between 2,000 and 6,000 computers in less than a day by taking advantage of a buffer overflow.
Mariner 18 lost due to missing NOT in program.
Department store anti-theft microwave device reprogrammed heart pacemaker, killing its user.
Autopilot error caused China Airlines 747 to stall near San Francisco.
I have lived with several Zen masters - all of them were cats.
His last invention was an evil Lasagna. It didn't kill anyone, and it actually tasted pretty good.
|
|
|
|
|
Cannot see your list due to the hardware failure of my monitor, sorry.
"In testa che avete, Signor di Ceprano?"
-- Rigoletto
|
|
|
|
|
Could it not be that it's the graphics card? In that case I might have a solution. DIY Analog VGA for 8 bit processors. Without programmable logic that will be a bigger board with about a pound or two of discrete logic, so let's throw in another processor to manage the graphics resources and do the rendering and that DMA interface to talk to the main processor again.
I have lived with several Zen masters - all of them were cats.
His last invention was an evil Lasagna. It didn't kill anyone, and it actually tasted pretty good.
|
|
|
|
|
Similar h/w v s/w on tape backups.
We used to backup a mini-computer which, to help reduce tape problems always re-tensioned the tape by running it from end to end and then back again before use. Them a new version of the tape came out - double the length, double the storage. This (obviously) took twice as long to re-tension. That was when we found out that there was a hardware 'fail safe' that if a tape spent too long rewinding, it assumed that the tape had snapped. So the new tapes were useless and were all thrown away (apart from the one that I have stashed away in my archive).
I have at least three other daft stories about that machine, but I'll save them for another day.
-------------------------
Then we got an IBM machine with nice cassette tapes. The backups to them could be sped up by using data compression. That was fine unless you needed to restore a machine - the data expansion was not available from a 'raw' machine so you could not rebuild from the backups.
|
|
|
|
|
OriginalGriff wrote: My code worked, but the hardware just wasn't up to it.
I'm writing this one down for, erm..."future use".
|
|
|
|
|
I don't think FAT32 is too much for an 8 bit based on the fact that I use it on 8 bit a lot. Specifically on the ATmega2560. Only issue is that chip can manipulate 32-bit integers (though not as a native word)
Fat32 is a bit more difficult to implement without that.
Try to see if you can use SPI to communicate instead of a UART? You can get 10s of MHz speeds
Nice thing is SPI can be used with SD cards since SD cards are SPI slave devices, if i recall anyway.
I don't know what you'd use to drive the SPI master from your setup - you could use another CPU, like an ESP32 to do it. But either way, SPI is where I'd start looking.
Real programmers use butterflies
|
|
|
|
|
The little processor was able to fly to Jupiter, visit all the moons and steer the failing probe into Jupiter's atmosphere after surviving years in Jupiter's radiation belt. I think it can tackle the file system without too much help. 
I have lived with several Zen masters - all of them were cats.
His last invention was an evil Lasagna. It didn't kill anyone, and it actually tasted pretty good.
|
|
|
|
|
I'm not thinking so much as a coprocessor, but more just using it as something you can break SPI out into individual data pins with.
Real programmers use butterflies
|
|
|
|
|
SPI is aserial protocal again and not extremely fast, at least not on the PIC microcontrollers I have seen. And that leads us to some other problems: Soldering SMDs, low voltage levels and level shifting. It's quite possible that I actually have raise the supply voltage to 6V in order to squeeze out a higher clock frequency, not lower it to 3.3V or even less.
I have lived with several Zen masters - all of them were cats.
His last invention was an evil Lasagna. It didn't kill anyone, and it actually tasted pretty good.
|
|
|
|
|
I do animation @ 320x240x16bpp over SPI @ 26mhz on the regular.
I mean, you could use 4 wire, something like used by SDMMC - that would get you higher transfer rates and it's still basically SPI, but it has 4 lines instead of one.
Anything faster, and you're going to need some dedicated hardware - if you want to run NVMe you're not going to do it very easily, particularly without some sort of controller in the middle. Same with SATA even, I think.
So what level complicatedness (i hesitate to use "complexity" here) are you looking to deal with?
Are you willing to put a relatively sophisticated drive controller into the loop?
If not, I'd consider SDMMC. It can give you about 2.5MB/s if not more?
I'd have to look into it again. But actually you're going to be limited anyway, same way I was because of FAT32 sectoring preventing you from doing large reads, severely limiting your throughput.
That's going to be your biggest hurdle once you decide on the interface, I think.
If you want fast I/O, I'd say use a flat binary blob right on the drive.
Real programmers use butterflies
|
|
|
|
|
VOLA - These Black Claws (Feat. SHAHMEN)[^]
I don't think any other band has made it into the SOTW as often as VOLA has.
I've known them since their debut in 2016 and I think I've had two SOTW's for every album since then (this one is the second SOTW from their third album, which will be released later this month).
They play pretty accessible metal, although it's quite poppy, if only because of the keyboard tunes and the singer's pleasant (clean) voice.
This song is a bit different in that it features Shahmen, a rapper.
I'm not a fan of rap in my metal, but VOLA (and Shahmen) does it quite tastefully!
Someone mentioned it's like KoRn meets Massive Attack and I can agree on that, although it also still sounds like VOLA.
SOTW and looking forward to the entire album! 
|
|
|
|
|
Nice.
I personally don't like talking/monologue during a song, but overall, not bad.
|
|
|
|
|
Great track  ... very listenable, mesmerizing riffs in many places, great visuals (but I had to shut my eyes at some moments ). Added them, perhaps again, to my list, thx ...
|
|
|
|
|
Wow! That was six minutes of mindless excrement, except for the dog. The dog was good. The blonde should have bigger hooters, too.
Will Rogers never met me.
|
|
|
|
|
Haters gonna hate, never thought you to be one of them 
|
|
|
|
|
To each his own! That's why we get choices.
Will Rogers never met me.
|
|
|
|
|
Supreme lover lost the right to new technology startup. (9)
I win, and I'm up on Monday!
"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
"Common sense is so rare these days, it should be classified as a super power" - Random T-shirt
AntiTwitter: @DalekDave is now a follower!
modified 14-May-21 7:40am.
|
|
|
|
General 
News 
Suggestion 
Question 
Bug 
Answer 
Joke 
Praise 
Rant 
Admin 
Submit an article or tip
