VMU as Memory?

Discuss modifications you have done or plan to do to your Dreamcast or any other hardware, or discuss devices you want to build. If your console does not work or is acting up, ask about fixing it in here.
Post Reply
unoproph
Insane DCEmu
Insane DCEmu
Posts: 141
Joined: Fri Mar 29, 2002 11:14 pm
Location: Who Cares?
Has liked: 0
Been liked: 0

VMU as Memory?

Post by unoproph » Wed Apr 10, 2002 7:32 pm

I was thinking...and I know it's probably been thought of, but what about using extra VMU's you have plugged into your DC as memory. I mean say most emu's will support a max of 2 controllers, and other then the 1 VMU you're using as your your saves you can have 3 others plugged into 2 controllers. Now, I'm not quite certain (because I'm new to this) how much megs are in a vmu (1, 2, or 4), but even at 1meg a VMU, I think it's give enough to dreamsnes to run at full speed (3 add'l megs total). but, if they are 4megs, that 12 extra megs of memory, even some mid-level Neo-Geo games might be able to work on MAMEDC. I was just thinking of this cause I was out looking at dig cams, and thought if those are considered memory sticks how about using vmus. If it's not possible that way. I threw a comment in on a linuxdc question about in the old days of win3.1 there used to be software that could be used as ramdoubling. Now, I imagine, it used to use hard drive space to "emulate" ram. But, if the vmu's are used as the hard drive let's say, then maybe there might be a way to use a ram program on them. Like befor any emu pops up, the ram software runs and searches all the memory ports for extra vmu, and allocates them as extra ram. And just like memory on a computer, when you shut off the machine, it frees the memory.

I don't know maybe I just went on a ramble of things that could possibly never work, and like I said it's probably already been discussed, but it never hurts to ask, you know.

Thanks for listening to my ramble,
Uno
sixteen-bit
Hardware Freak
Hardware Freak
Posts: 3246
Joined: Sat Dec 29, 2001 3:45 pm
Has liked: 0
Been liked: 0

Post by sixteen-bit » Wed Apr 10, 2002 7:39 pm

Sorry to put a downer on your ideas, but the Dreamcast standard VMUs store 1Megabit of data in flash RAM which is 128KB in "real" storage space. Even the 4Mb cards only store 512KB.

Also, the data transfer rate for stuff going into and out from the VMU is not really great enough to aid emulation with extra memory. Sorry.
User avatar
|darc|
DCEmu Webmaster
DCEmu Webmaster
Posts: 16198
Joined: Wed Mar 14, 2001 6:00 pm
Location: New Orleans, LA
Has liked: 29 times
Been liked: 6 times
Contact:

Post by |darc| » Thu Apr 11, 2002 1:03 am

yeah, each VMU is really small. The time it takes for data to go to the VMU and back is not short. That's why saving games on a VMU taks a few seconds.
It's thinking...
infinite-nothing
Mental DCEmu
Mental DCEmu
Posts: 360
Joined: Mon Jan 21, 2002 6:01 pm
Has liked: 0
Been liked: 0
Contact:

Post by infinite-nothing » Thu Apr 11, 2002 8:32 pm

i have no idea if this is possible but could you build some cable that would connect from the vmu port to your pc and do sumthin with that
"your best......your best, losers always whine about there best. Winners go home and f**k the prom queen"-Sean Connery"-
unoproph
Insane DCEmu
Insane DCEmu
Posts: 141
Joined: Fri Mar 29, 2002 11:14 pm
Location: Who Cares?
Has liked: 0
Been liked: 0

Post by unoproph » Thu Apr 11, 2002 10:15 pm

What about creating something that connects to the comm or serial port, that could be extra memory, and a program boots up before hand the maps all the connects before the emu does. that's probably not possible anyway, but trying to throw out ideas. I think if the dc scene (i know i'm new to this, but i did read a post on here asking about how long you think this'll last) is going to be around for a long time, there needs to be something that boots performance somehow, by way of ram, or an external hd.
EvilSporkMan
God Of All Things Sporkish
God Of All Things Sporkish
Posts: 755
Joined: Sat Feb 16, 2002 1:04 pm
Location: Somewhere over the cuckoo's nest
Has liked: 0
Been liked: 0
Contact:

Post by EvilSporkMan » Fri Apr 12, 2002 6:12 am

*blink*
something that connects to the comm or serial port
uh...that would be popularly known as a coders' cable? (BBA is good too) I'm sure if someone like Dan Potter REALLY wanted to they could do something with it, but don't hold your breath.
You can go anywhere you want if you look serious and carry a clipboard.
DoughBoy
Yes, that's right I'm a
Yes, that's right I'm a
Posts: 537
Joined: Wed Feb 06, 2002 3:05 pm
Location: Toronto, Canada
Has liked: 0
Been liked: 0
Contact:

Post by DoughBoy » Fri Apr 12, 2002 3:41 pm

VMY is MUCH slower then actual phsycial ram. Secondly, these ideas won't wokr (nto to put a downer) because it's waaaaaaaaaaay too complicated, extremely complicated
Another great and interesting post brought to you by the DoughBoy!

P.S. I'm looking for A Turbo Express, PM me if you got one.
User avatar
az_bont
Administrator
Administrator
Posts: 13567
Joined: Sat Mar 09, 2002 8:35 am
Location: Swansea, Wales
Has liked: 0
Been liked: 0
Contact:

Post by az_bont » Sat Apr 13, 2002 5:53 am

The problem with connecting it to a PC is that your DC has to be near a PC, which isn't always convinient if it's under your living room TV or in your bedroom.

I had an ideo for a way to speed up all emus. It's a long shot but here goes. Someone could develop a universal and external RAM expansion pack for the DC, along the same lines as the N64 expansion pack. I said it was a long shot.

If not, what about some way of using PC RAM to upgrade the DCs power? The only problem there is that you lose the best thing about DC emulation - Everyone can use it.
Sick of sub-par Dreamcast web browsers that fail to impress? Visit Psilocybin Dreams!
infinite-nothing
Mental DCEmu
Mental DCEmu
Posts: 360
Joined: Mon Jan 21, 2002 6:01 pm
Has liked: 0
Been liked: 0
Contact:

Post by infinite-nothing » Sat Apr 13, 2002 12:19 pm

if you did replace the DCs ram with computer am how exactlly would you go about connetting it and such
"your best......your best, losers always whine about there best. Winners go home and f**k the prom queen"-Sean Connery"-
sixteen-bit
Hardware Freak
Hardware Freak
Posts: 3246
Joined: Sat Dec 29, 2001 3:45 pm
Has liked: 0
Been liked: 0

Post by sixteen-bit » Sat Apr 13, 2002 2:31 pm

Sorry to put another downer on your plans guys, but after discussion in the harware forum a while back it was discovered the Dreamcast ports are not really cut out for this kind of stuff.

The maple bus seems to operate in the low megabit range, which is fine for controllers and writing to the flash RAM of the VMU but useless for external RAM.
Despite my guess that the DC serial port is faster than the one in your PC, it will still only push a few hundred kilobits/sec so is likely slower than the maple bus too.

The expansion port where the modem and BBA plug in is the fastest external I/O port in the dreamcast but appears to not have a dedicated data bus. It looks like it shares a 50mbit/s bus with the DSP and sound chips; which again wouldn't provide enough bandwidth for useful external memory. To use external memory we would need a dedicated data bus in the high mega-/gigabit range.
XantiaX
Mental DCEmu
Mental DCEmu
Posts: 405
Joined: Tue Dec 04, 2001 7:01 am
Location: UK
Has liked: 0
Been liked: 0
Contact:

Post by XantiaX » Mon Apr 15, 2002 6:50 am

just a quick point because i have to leave but i remember seeing somewhere online about a converted vmu that had 128mb flash memory bunged onto it, how bouts that?
..::XantiaX::.. aka Chim-Chim Cootiesniffer
Lartrak
DCEmu Respected
DCEmu Respected
Posts: 6166
Joined: Thu Jan 31, 2002 9:28 pm
Has liked: 0
Been liked: 0

.

Post by Lartrak » Tue Apr 16, 2002 11:10 am

I believe the serial port runs at 1.5 Mbits. Still to slow, but thought I'd mention it.
Post Reply