Tape and Disk load speeds

[kool kitty89]

This came up a couple times recently on Sega-16, here: http://sega-16.com/forum/showthread.php?p=279153 and some conflicting stuff even more recently here: http://sega-16.com/forum/showthread.php?p=293823

http://sega-16.com/forum/showthread.php?p=294074

 

So how fast was the Atari 8-bit tape drive compared to C64, Apple II, CoCo, ZX Spectrum, Amstrad CPC, etc?

 

And how did the disk speeds compare?

Edited September 9, 2010 by kool kitty89

[carmel_andrews]

c64 tape speed without 'turboloaders' would be as slow as the A8

 

c64 disk spped is probably similar to the A8 (but you do get slightly more storage then an unmodded a8 drive)

 

spectrum tape speed rather depends on the quality of third party tape recorders (some are good, some are not so good)

 

Dunno about spectrum disk stuff (didn't get much into the speccy)

 

Amstrad tape speed was variable and could be programmed to going up to 19200 bps

 

dunno about Amstrad disks

 

A8 tape speed was typically 600 baud but could be software programed to 1200 baud

 

I think the standard A8 disk speed was 19200 bps

Edited September 9, 2010 by carmel_andrews

[+orpheuswaking]

Are you crazy?

 

Stock Commodore disk speed vs Stock Atari disk speed is day and night... Due to a problem in the C= 1541 original firmware that had to be rewritten and reducing speed...

 

Now however that doesn't mean they couldn't be made to go faster (hardware & Software routines could speed them up to atari speeds fairly easily)...

 

But stock drives were SLOW!!!!

[kool kitty89]

Anecdotes and other information on the disk speed issue seems fairly consistent (C64 was SLOW without custom/turbo loaders and A8, Apple II, and mot others were fairly fast -better than the turbo/custom loaders of the C64 even), but I've been getting more mixed impressions on the tape speeds from the previous discussions I mentioned, in particular you have this:

 

While the C64 was superior in a number of ways (SID chip), the floppy more than made up for the lack of fail. It has the distinction of being slower than cassette drives from the previous generation... by a WIDE margin. It was bad enough to drive people into fits of destruction, and the music that destroyed the heads was part of that. It's the main reason I never bothered to get a C64 until many years later when I picked up one with a bunch of stuff for $5.

 

http://sega-16.com/forum/showthread.php?p=279153

The 8bit Atari floppy was LIGHT YEARS faster than even the best custom loader for the C64 floppy. The A8 cassette was much faster than the C64 normal loader. A "fast" custom loader could get about the same speed as the A8 cassette. The A8 cassette had two speeds: fast and slow. Games loaded in fast mode, while the BASIC loaded data in slow mode due to how slow Atari BASIC was.

 

The Apple II floppies were also much faster than the C64, but I don't know about the Apple cassette drives as I've never seen one before.

 

If the C64 cassette is slower than the floppy, I'm glad I never had to deal with one. I think I'd probably have gone insane and started shooting people from a clock tower.

He's talking mainly in comparison to C64 disks too, not tapes. (ie A8 disks and floppies vs C64 disk alone)

and following comments regarding the CoCo tape being considerably faster than the C64 as well, and comments about the general functionality of the A8 drive, its use of stereo (for a 2nd track with audio), data encoded in FSK, etc, on the following page: http://sega-16.com/forum/showthread.php?t=12564&page=10

 

But then there was this:

Scratch that, I'm not taking your words for it, I just ran into an old thread on Retrogamer about load times and everyone categorically agrees that the A8s have the slowest tape load times, many of the examples they are giving are over 20 minutes, and many of the people posting comments I know are generally very reliable.

 

Someone mentions Bounty Bob Strikes Back on XL as taking over 20 minutes to load, the Spectrum version loads in 3 and a half minutes.

 

Another thread I ran into on Atariage makes it sound as though they never managed to speed up in the same way as C64 games did either, they're talking about ~10 minutes for a 64k load.

 

And a following post including an anecdote about 20-30 minute load times on the A8.

Those were all from the European perspective I think, so maybe there was some odd tendency to use the slow tape drive speed to load instead of the fast speed? (as with BASIC)

Edited September 9, 2010 by kool kitty89

[kool kitty89]

How would CoCo loading speeds compare? (wiki lists that as approximately 1500 bits/s, not sure of the accuracy of that though)

 

I've also seen comments about the CBM1541 (with standard firmware) was slower than many of the contemporary (or earlier) cassette loading speeds. (the C64 tape with normal loader seems to be among the exceptions to that -and I think the VIC-20 as well, unless it was different from the C64 in that regard, and probably the TRS80 model 1 -which was a bit finicky in general with the tape on top of that from what I understand)

[JamesD]

The CoCo was 1500 baud but you could also save and load at double speed if you knew what you were doing. The CoCo had one of the most reliable tape interfaces due to a patented storage method unique to it.

There was a topic on Atariage about tape load speeds. Lots of computer tape speeds were listed.

[kool kitty89]

The CoCo was 1500 baud but you could also save and load at double speed if you knew what you were doing. The CoCo had one of the most reliable tape interfaces due to a patented storage method unique to it.

There was a topic on Atariage about tape load speeds. Lots of computer tape speeds were listed.

Ah thanks, I must have missed that when I searched it before.

 

http://www.atariage.com/forums/topic/155625-tape-and-disk-loading-speed-on-8-bit-computers/

 

 

That's still a bit vague though. It mentions 600 baud for the A8 tape drive, but that doesn't necessarily mean that's the only speed. Given the comments from Chilly Willy listed above it seems the tape drive itself had fast and slow speeds, with BASIC always using the slow speed but games (and presumably any other software not using BASIC) would load in the "fast" speed. So if 600 baud is the speed used for BASIC, the Fast speed is still not listed. However, it was claimed that it was notably faster than the C64 disk drive.

 

And as the other thread addresses to a small extent, the C64 tapes got much faster with custom loaders used with roughly a 5x speed increase from the 15-20 minute load times for early "full sized" (ie close to 64k) games and 3-5 minutes from games at the end of the 80s and in the early 90s. (in the case of European releases at least) In the case of games, the load speed for the speccy seems pretty consistent with a moderate increase in load time for some late games. (not sure if that was in the context of 128k specific games though -which would mean significantly faster load times)

That 1350 baud figure seems to match up pretty well with Spectrum 48k games loading in approximately 3 minutes. (the largest 48k games would be approximately 40 kB with the rest for graphics and work RAM -less than that even if double buffering was used for graphics, but few if any games seem to do that, hence the screen tearing)

 

 

The comments about SIO being a limiting factor for disk speed seems to conflict with some comments in other discussions mentioning the A8 disk drives didn't really come close to maxing out the SIO bandwidth. (unless that comment to the contrary was specifically in the context of custom/fast loaders which did hit the wall for SIO)

Edited September 17, 2010 by kool kitty89

[JamesD]

That's still a bit vague though. It mentions 600 baud for the A8 tape drive, but that doesn't necessarily mean that's the only speed. Given the comments from Chilly Willy listed above it seems the tape drive itself had fast and slow speeds, with BASIC always using the slow speed but games (and presumably any other software not using BASIC) would load in the "fast" speed. So if 600 baud is the speed used for BASIC, the Fast speed is still not listed. However, it was claimed that it was notably faster than the C64 disk drive.

600 baud was the Atari ROM tape routine speed. Custom loaders could load faster than the standard ones on any machine out there since loading is just done with sampling and software timing loops.

Only the CoCo can do high speed loads/saves without a custom loader due to its high speed mode and RAM based parameters for the tape routines.

<edit>

I said any machine but I seem to remember one machine used a separate CPU for the tape interface. I'm not sure if it supported high speed loaders. I *think* it was the NEC Trek but I'm not sure.

Edited September 17, 2010 by JamesD

[kool kitty89]

That's still a bit vague though. It mentions 600 baud for the A8 tape drive, but that doesn't necessarily mean that's the only speed. Given the comments from Chilly Willy listed above it seems the tape drive itself had fast and slow speeds, with BASIC always using the slow speed but games (and presumably any other software not using BASIC) would load in the "fast" speed. So if 600 baud is the speed used for BASIC, the Fast speed is still not listed. However, it was claimed that it was notably faster than the C64 disk drive.

600 baud was the Atari ROM tape routine speed. Custom loaders could load faster than the standard ones on any machine out there since loading is just done with sampling and software timing loops.

Only the CoCo can do high speed loads/saves without a custom loader due to its high speed mode and RAM based parameters for the tape routines.

<edit>

I said any machine but I seem to remember one machine used a separate CPU for the tape interface. I'm not sure if it supported high speed loaders. I *think* it was the NEC Trek but I'm not sure.

OK, but did most games tend to use custom loaders by default? (and was the 1350 baud rate for the Speccy and 1500 baud rate for the CoCo standard ROM/BASIC/BIOS routines or commonly used format for custom loaders?)

 

Plus, I'd gotten the impression that it wasn't just custom loaders using higher data density on the tapes, but 2 actual tape spool speeds the drive could do. (with BASIC limited to the slow speed only)

 

 

I was poking around some more and got some widely varying figures for the C64 including 300 baud for the cassette here: http://www.picaxeforum.co.uk/archive/index.php/t-10899.html which seems exceedingly slow and significantly slower than what the PET was already doing (with an effective 750 baud loading listed on wiki and I also found 500 baud listed for the recording speed -in both cases using the typical commodore redundant data format).

In the case of Commodore systems, given the halved bitrate from the redundant data format, a custom loader could double the speed just by eliminating that redundancy alone and using an otherwise similar density format. (ie jump to 1500 baud in the case of the format used on the PET)

[svenski]

From memory it wasn't possible to use software turbo loaders for the Atari 8-bit due to the hardware. Sure you could have a screen that loaded up first that appeared like a turbo loader but cassette loading times on the 8-bit were always slow.

 

Sure, some games loaded fast but that depended on the size of the game. You could buy a game on tape, look at the amount of actual tape on the cassette and from there know if it was going to be quick, average or maybe an hour of load time.

 

There were several hardware turbo loader modifications. I think a couple were designed behind the then Iron Curtain, or the badly moth eaten about to fall down Iron Curtain, and one was done by Richard Gore, Micro Discount, in the UK.

 

Richard's mod was called the "Rambit" I believe and he sold special versions of games on cassette to take advantage of the Rambit.

 

I think every turbo loader required its own software, so it wasn't a case of doing the mod and then being able to load a normal game tape at twice the speed.

 

With the Atari you could spend anywhere between half an hour to over an hour , depending on the game, waiting for the damned thing to load.

 

As far as disk is concerned, you only have to connect a floppy drive to an Atari and realise that the 8-bit was destined for use with disk drives. You can't compare Atari 8-bit drives with Commodore for example, as for the C64 the use of floppies was more like just an extra, slow, storage medium but with the Atari it was an empowering, life changing experience.

[JamesD]

OK, but did most games tend to use custom loaders by default? (and was the 1350 baud rate for the Speccy and 1500 baud rate for the CoCo standard ROM/BASIC/BIOS routines or commonly used format for custom loaders?)

Those were the standard ROM routines/speeds. The tape software I had for the CoCo used the standard tape routines but I'm not sure about other software. I know there were custom loaders for the Speccy... they were even advertised in Speccy magazines. Beyond that I can't tell you much.

 

Plus, I'd gotten the impression that it wasn't just custom loaders using higher data density on the tapes, but 2 actual tape spool speeds the drive could do. (with BASIC limited to the slow speed only)

The tape drive only has one motor speed. There was some sort of dual speed cassette drive for the TRS-80 Model I but I never saw it available for any other machine.

 

If the tape drive could only transfer at one speed over the serial interface (unlike the floppy), a custom loader could still load a compressed game from tape in less time.

Most machines just used some sort of analog circuit directly attached to the CPU. Loading just required sampling the incoming values with software timing loops to load. Saving did things in the reverse order. Change the rate you write data and sample it and you have a higher baud rate.

 

I was poking around some more and got some widely varying figures for the C64 including 300 baud for the cassette here: http://www.picaxeforum.co.uk/archive/index.php/t-10899.html which seems exceedingly slow and significantly slower than what the PET was already doing (with an effective 750 baud loading listed on wiki and I also found 500 baud listed for the recording speed -in both cases using the typical commodore redundant data format).

My understanding was that all the commodores supported the same baud rate as the PET. I thought that was 300 baud but maybe that was partially due to the redundancy.

I wouldn't trust Wiki too much, how accurate it is depends on who edited it.

Recording and playback speed should be the same.

[JamesD]

http://www.faqs.org/faqs/atari-8-bit/faq/section-20.html

[TMR]

On average, an unaccellerated C64 tape load will be roughly the same as an A8 tape load, around thirty minutes for 40K or thereabouts (when i was waiting for my 800XL to load games, i'd play VIC 20 stuff, since i had quite a few 8K titles converted to turbo loading it was possible to set both off at the same time and have several games on the VIC before the A8 was done!) and that can immediately be halved on the C64 without even changing the transfer speed because the stock routines keep two copies on the tape (one to load and the other to verify against) - only saving one copy immediately strips 50% of the loading time away. Then the programmer could speed up the transfer rate significantly, the loader used by Martech on the game Crazy Comets could pull in the entire game in 65 seconds (from pressing play on tape to the game starting so it includes the fast load header coming in at stock speed) or thereabouts, that's 19.5K long so a complete fill of the C64 memory would take about three minutes, perhaps a little longer.

 

C64 stock disk is faster than C64 stock tape, C64 accellerated disk can be very quick indeed and several schemes claim upwards of twenty times faster than stock; the loader on the Action Replay cartridge (which is technically software since there's no hardware trickery between the C64 and drive) can read 64K into memory within about seven seconds but disk-only systems would need a header coming in at stock speeds first so take a little longer.

 

Slower tape and disk schemes on the C64 can handle other code running whilst data comes in too; Mastertronic and Players both had loading game schemes where a small game could be played whilst the main one loaded, Hawkeye and Flimbo's Quest both have bonus screens after each level that play music and animate whilst racking up the score as the next level loads and Dragon's Lair 2 loaded the next level whilst the current one was being played.

[kool kitty89]

What sort of hardware limits prevented the A8 from fast custom loaders? (it doesn't seem like that was really the issue) Or was that simply referring to the speed limits of the Atari cassette drive? (in which case 3rd party drives/interfaces would circumvent that, and compression or custom formating would be other possibilities without altering the spool rate -any custom loaders using different format would either need to use a cart/disk program, or possibly load via the tape -ie have the custom loading program in the normal 600 baud format and switch to the custom format after that's loaded into RAM)

 

Any why would a program load take over 30 minutes, let alone and hour if we're talking 600 baud for the standard ROM routines on the A8?

600 baud would be double that of the VIC/C64's 300 baud rate, albeit 1/2 that of the Apple II and less than 1/2 that of the Spectrum of VIC-20.

 

At that speed (with continuous loading) a 40kB program should have loaded in approximately 9 minutes on the A8, and a 16k load should have taken under 4 minutes. (600 baud is just under 4.4 kB a minute at 4500 bytes/minute)

Edited September 19, 2010 by kool kitty89

[JamesD]

Amstrad tape speed was variable and could be programmed to going up to 19200 bps

The info I can find says 1000 or 2000 baud were in the ROM. 19200 would be a fast loader.

[kool kitty89]

Any idea why loading times would ever be 30+ minutes for Atari tapes? Even with the 600 baud normal loader it would be 2x the speed of the VIC/C64 normal loader. 600 baud is 75 bytes per second (4500 bytes/minute), so even a 48 kB program should load in about 11 minutes. Smaller programs/games would load faster, of course: 8k stuff should be roughly 1 min 50 sec, 16k stuff (a lot of games seem to be in that range) should be well under 3:40, 24k about 5:30, and 32k 7:20.

Edited September 20, 2010 by kool kitty89

[jmetal88]

CoCo tape speed is insanely fast compared to Atari tape speed.

 

EDIT: There is a drawback though - the entire system locks up until the program is done loading or a read error is encountered. Well, actually that isn't much of a drawback in my opinion, but some people think it is.

Edited September 20, 2010 by jmetal88

[kool kitty89]

Did the Apple II (or Spectrum, etc) lock the system during tape loads as well? (or some custom loaders for that matter)

 

But yes, it appears the A8's standard OS tape loading routine was only 1/2 the speed of the Apple II and even less than that compared to the Speccy or CoCo. It was 2x as fast as the VIC/C64 normal loaders though, and faster than the TRS-80 as well. (albeit the level 2 BASIC for the TRS-80 was still faster than the VIC/C64 at 500 bps to Commodore's 300 -level 1 BASIC was only 250 baud though)

 

So the Apple II should load a 16k program from tape in 1:50 and the CoCo in 1:30 or close to 45 seconds at double speed. (maybe closer 1 minute depending on the actual speed -double speed only works when reading from ROM, RAM is still normal speed)

Edited September 21, 2010 by kool kitty89

[TMR]

Did the Apple II (or Spectrum, etc) lock the system during tape loads as well? (or some custom loaders for that matter)

 

Can't comment about the Apple II, but the Spectrum wasn't locked; there were animated effects one some protection schemes, loading games and last year a

that loads whilst executing some fairly complex code.

[kool kitty89]

Did the Apple II (or Spectrum, etc) lock the system during tape loads as well? (or some custom loaders for that matter)

 

Can't comment about the Apple II, but the Spectrum wasn't locked; there were animated effects one some protection schemes, loading games and last year a

that loads whilst executing some fairly complex code.

Ah, OK, so one thing locking the system would mean for the CoCo is no loading screen animation or music as with a lot of C64/Speccy/CPC stuff. (not sure about Atari)

 

I still don't understand the reason for half hour load times on the A8, even for 48k loads. For the C64 at the 300 baud rate I could see 20-30 minutes for large games (obviously less for custom loaders), but the Atari stuff of the same size should have been 1/2 that tops. (actually probably less than 1/2 for the higher range unless there were any tape programs that pushed close to 64 kB on the A8, without custom loaders of course)

[JamesD]

Did the Apple II (or Spectrum, etc) lock the system during tape loads as well? (or some custom loaders for that matter)

 

Can't comment about the Apple II, but the Spectrum wasn't locked; there were animated effects one some protection schemes, loading games and last year a

that loads whilst executing some fairly complex code.

To the best of my knowledge, all all systems that used the CPU and software timing loops to do the loading locked the system.

Fast loaders could replace delay loops with pieces of the animation code a fixed number of clock cycles in length. So instead of doing nothing while waiting to read the next bit, the CPU would do a piece of the animation. That was possible on any machine like that including CoCo, Apple II, etc...

However, disk drives were very popular on the Apple and it's tapes were a little finicky so I don't think anyone did that on the Apple.

The CoCo commonly had load screens but tapes loaded so fast I don't think people bothered on it. No need for a speed loader = a lot of work just to be able to do animation during a load.

[ed1475]

For fun, I tested the tape and 5.25" disk drive speeds on a Coleco ADAM using a 3 page single spaced word processing document.

 

 

tape drive load- 45 seconds save- 105 seconds

 

disk drive load- 25 seconds save- 27 seconds

Edited September 25, 2010 by ed1475

[+Stephen]

Standard Atari disk speed was 19,200 baud which when using a real drive gave about 1K/sec. This is terribly slow compared to what the SIO bus can do. Below is a video showing 127840 baud. I do a single pass copy of a 183K disk and get 21 sec for 180K read = 8.57KB/sec, and 24 sec for 180K write = 7.5KB/sec. Parallel based storage solutions such as a compact flash to IDE adapter can achieve 60K/sec when using a DOS based file system, or roughly 80K/sec when doing raw data transfers.

 

The only Atari tape speed was SLOW. The FSK decoding was done in hardware so you couldn't bump too far past the stock 600 baud.

 

http://www.youtube.com/watch?v=414Fhl7qTiE

[Rybags]

Using software, I got tape to about 800-850 bps reliably. The OS in fact can handle a range of speeds from something like 500-900.

The baud rate for writing is hard-coded but I just got around it by using a VBI that forced values into the AUDF registers to increase it.

 

You can't directly quantify baud rate to load time, it's a bit more complex. The leader has to be at least 5 seconds or so. The IRGs are about 0.25 seconds, so by default you've got ~ 2 seconds of wasted time per KB loaded.

Also, tape records are 132 bytes of which only 128 are data, so that's around 3% overhead there.

 

When I only had a 1010 I wrote a custom hi-speed loader for the AsmEd cart image. It had a standard boot sequence of about 2 or 3 blocks, then did a SIO call that loaded the entire 8K image as one huge block without gaps.

 

The entire thing was saved at high speed and I used a shorter leader (just don't press REC until a few seconds has passed). It loaded in little over half the time that a normally saved version would have.

 

The added bonus of such custom loaders is that they can be made practically impossible to copy using the computer, it's kinda surprising that hardly any software used them.

[carmel_andrews]

Didn't synapse's tape version of dimension X, have high speed loading....I seem to recall it did (either that or it loaded in data in bigger chunks by using i believe modified DCB or IOCB routines)