Serial port speed read write benchmark

[Ian Micheal]

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4X CD-ROM 600 KB/sec

serial port is 400k bits per sec. or 50k bytes per sec.

???
SD - 4-7 Mbit (depends on the quality of the adapter and SD card )
HDD - 80+ Mbit (this is where the real speed )

Not as slow as i see a lot claim

[Ian Micheal]

When many people think of it as slow it's due to retail games using DMA and cdda.. Also the 50kb sec and 150 kb a sec that people think is coders cables for dev not dreamshell loading things with it.. DLC content loading would be very fast not loading for days as some might think..

For loading data it's as fast as cdr.. plus the fact you have reading from cdr asd serial port at the same time no stop start.. it's faster then swapping in swap disk or downloading for vmu which would be tiny space..

The thing not every one has one why not it's $15 needs no mods plugs in the back can be included with indie release if wanted .. there are nice metal well made for cheap now versions.. that look like sega made them..

Dreamcast was going to have zip drives this is just as fast and more space..

[Ian Micheal]

Not talking the rubbish serial ports of old these use metal connected and are very well made

Indie game could have edition including and standard if you have it.. Just code to look for it if not load the normal game pretty simple stuff

loading the main bin from SD card is faster then a cdr btw having the high speed data on the cdr is how i did it works perfect can stream cdda on the cdr and load all the data on the sd card hybrid file system..

Advantage update-able main bin for -- bug fixes and data
Write space for replays and screen shots of you playing the game ---
Unlimited save space..

Faster main bin loading does not have to load other things while the other drive plays music or a video

$15 just seen them on
aliexpress.com for $10

Any indie game could use it for more levels replays save space etc dont need dreamshell to load it can use fat32loader included in kos to do all that as the same time as the main game loads

I have showed this it's why i got on hackaday

idea's and uses are endless you have read write space that can be used at the same time as cdr whats not to like

[MoeFoh]

The light bulb just turned on on how the serial port works with a sd card reader to achieve a high bitrate.

The Dreamcast does not use a UART, instead relies on the CPU for control.

The Dreamshell serial port driver outputs a signal directly to the sd card itself and vice-versa (very clever).

Right? Wrong?

[Ian Micheal]

That's pretty much it as far as i can tell as well I think!! Common it's too slow is from coders using the serial cable [ coders cable]]

I think Atomis wav conversions ports which play perfect on it not a cdr should of shown people by now that if the files are more like rom it's fast and useful

Main thing for me is being able to read from 2 sources at the same time.. Many things if you coded it for you could do it's only a benefit.. I ve rleasing my hybrid homebrew ports soon

Simple use DOOM with full CDDA loading levels while playing CDDA at the same time this cant be done on cdr it has to stop to load data etc



Unpacking and loading levels From both cdr and sd card at the same time

[Ian Micheal]

Other use unlimited music play with flac mp3 mp4a 10 gig of mp3s wavs HQ formats I can stream flac auto on serial port for example ON the fly in a hombrew game using dream eye take a picture of your self dump and load direct as your avtar etc many things to bring the dreamcast way a head can be done..

I hope the it's to slow stuff will stop more It plays Atomis wav games perfect how can we use it will prevail


Serial port loading and playing Atomiswave games a cdr cant do this
https://www.youtube.com/playlist?list=P ... 1jVAPzHTYV

Atomiswave faster than speed DCMC DREAMSHELL SD CARD
loads in 4 secs Time stamp https://youtu.be/hGaisUoyDNs?list=PLnqO ... zHTYV&t=88


Plays perfect in game etc

Hope this helps people understand what can be done..

Thanks megavolt for your work..

[MoeFoh]

The coders cable has to use a serial to serial bridge chip so the speed is limited. Whereas, the sd card itself is wired directly to the serial port on the Dreamcast via the sd card adapter. There is newer type of serial cable that uses a serial to usb chip (FT232R).

What a fascinating machine the Dreamcast is - way ahead of it's time. Not a day goes by that I don't learn something new - thanks to guys like Ian.

ian, I tested the GENS4SSP cdi you mentioned a few days ago. Wow, it's awesome! Get the latest release here: viewtopic.php?f=5&t=14727&start=50#p156059

CDI of GENS4SSP I made for GDEMU/GDMENU is below. The padding file has been removed and a disc icon added.

[Ian Micheal]

The coders cable has to use a serial to serial bridge chip so the speed is limited. Whereas, the sd card itself is wired directly to the serial port on the Dreamcast via the sd card adapter. There is newer type of serial cable that uses a serial to usb chip.

What a fascinating machine the Dreamcast is - way ahead of it's time. Not a day goes by that I don't learn something new - thanks to guys like Ian.

ian, I tested the GENS4SSP cdi you mentioned a few days ago. Wow, it's awesome! Tomorrow, I'm going to release a GDEMU version with the giant sized pad file removed.

Yes great work by TapmN one of the best coders in the scene

I think it will only get better the next version for sure.. If he was using his own pvr driver i think you see even more amazing things..

Leaps and bounds past what the smash pack sounded like or run like.. Real 60fps

[MoeFoh]

Modifying DOOM to use both the sd card reader and cdr is brilliant! Ian is always on the cutting edge of what the Dreamcast can do. If you are not following him, you should.

[Cass]

The coders cable has to use a serial to serial bridge chip so the speed is limited. Whereas, the sd card itself is wired directly to the serial port on the Dreamcast via the sd card adapter. There is newer type of serial cable that uses a serial to usb chip.

What a fascinating machine the Dreamcast is - way ahead of it's time. Not a day goes by that I don't learn something new - thanks to guys like Ian.

ian, I tested the GENS4SSP cdi you mentioned a few days ago. Wow, it's awesome! Tomorrow, I'm going to release a GDEMU version with the giant sized pad file removed.

Yes great work by TapmN one of the best coders in the scene

I think it will only get better the next version for sure.. If he was using his own pvr driver i think you see even more amazing things..

Leaps and bounds past what the smash pack sounded like or run like.. Real 60fps

Only just tried this - it's amazing. Even the sound on SOR2 is really close. Definitely better than my cousin's old model2 Megadrive back in the day.