Denial

I have one of these floppy drives, which were basically 1541 clones with an external power supply. This drive apparently ships with a JiffyDOS 5.0 ROM and a second socket that can be populated with an alternative ROM and activated with a dip switch. I used the drive with my stock C64 back in the day, and I never touched the ROM switch which is still in its default position ("0") which according to the manual is "JiffyDOS".
Recently I dusted off the drive and connected it to my ZoomFloppy interface, and opencbm/cbmxfer identify it as 1541 with JiffyDOS indeed.
Two questions:
1) if the drive comes with JiffyDOS, how come it works with the stock kernal (both in the real machine and in VICE)? Is JiffyDOS "backwards" compatible with the stock kernal i.e. does it switch to CBM DOS mode automatically if JiffyDOS is not detected on the computer?
2) assuming I get the ROMs, can I use the drive with JiffyDOS in VICE?

LoadError wrote:I have one of these floppy drives, which were basically 1541 clones with an external power supply. This drive apparently ships with a JiffyDOS 5.0 ROM and a second socket that can be populated with an alternative ROM and activated with a dip switch. I used the drive with my stock C64 back in the day, and I never touched the ROM switch which is still in its default position ("0") which according to the manual is "JiffyDOS".
Recently I dusted off the drive and connected it to my ZoomFloppy interface, and opencbm/cbmxfer identify it as 1541 with JiffyDOS indeed.
Two questions:
1) if the drive comes with JiffyDOS, how come it works with the stock kernal (both in the real machine and in VICE)? Is JiffyDOS "backwards" compatible with the stock kernal i.e. does it switch to CBM DOS mode automatically if JiffyDOS is not detected on the computer?
2) assuming I get the ROMs, can I use the drive with JiffyDOS in VICE?

Before I answer your questions, did you check that your drive is in fact equipped with JiffyDOS by reading the status channel at power up ?

On a normal 1541, this reads "73,CBM DOS V2.6 1541,00,00".

On a drive equipped with JiffyDOS, it reads: "73,JIFFYDOS 5.0 1541,00,00"

eslapion wrote: On a drive equipped with JiffyDOS, it reads: "73,JIFFYDOS 5.0 1541,00,00"

That is indeed the output of "cbmctrl status 8" after powerup.

To be pedantically precise, my drive is not truly an Oceanic OC-118 Excelerator+, rather a clone of it, labeled "KY-1000" (no brand).
I bought it new around 1989 in Italy for the nominal equivalent of 120 Euros. It is identical to the OC-118, and the user manual is also identical (I found an OC-118 manual online).
I used it both with the C64 and with the VIC-20, both with the stock kernel, and it behaved exactly like a C1541 (slooooooow). So I decided to purchase an accelerator cartridge which once again was a clone of some other product (I think some version of the Action Replay), and this resulted in a dramatic speed increase (or a ludicrous increase if you saved a freezed state).
Back to the KY-1000, the whole manual details the standard CBM DOS 2.6 commands, no mention of JiffyDOS and/or DOS Wedge commands at all.
The only mention of JiffyDOS is in this awkward sentence in the last page:
"5. Where U4 location is a 28 pin IC socket and builds without I.C the purpose of U4 is offering more options to user to equip their own DOS. Besides Jiffy DOS, it is important that your ROM has to be a 27128 16K bytes only. Please set up dip switch as follow:
SWITCH 3: OFF=Jiffy DOS, ON=U4 ROM.
Above 5 point is a reference for the user of KY-1000H only."
There is no way to tell if my drive is a KY-1000H, but as I said it advertises as JiffyDOS 5.0 at boot, and it does have the n. 3 dip switch. The way I gather it anyway, it means that the KY-1000 only came with JiffyDOS and the KY-1000H had an empty socket for an alternative DOS.
Just for the sake of culture, I would like to find out if my drive is capable of higher speeds in conjunction with a JiffyDOS ROM on the Commodore machine (real or virtual), and to understand why it works flawlessly with the stock kernal (albeit in "slow" mode).

Yes, JiffyDOS-equipped drives work with standard C64 kernal also, it will just have no speedup.

OK, so if I were to connect my drive to a JiffyDOS equipped C64 (or VIC-20) it would seamlessly switch to JiffyDOS operations, right?
And what about VICE, are the JiffyDOS ROMs even available as dumps, and would they work in VICE with a physical drive?

Actually, the question can be expanded/morphed into a more generic one: which fast load methods are available in VICE using a ZoomFloppy/XUM1541 interface and a 1541 type drive? None of the fast loader cartridges I tried in x64 worked (by working I mean "it loaded the game from the real drive and it loaded it at a faster speed than the stock 1541 speed").

I've found this rather unnerving page:
https://groups.google.com/forum/#!topic ... qU70vj9c0s
They are saying that the ZoomFloppy can't use any speed loader or native DOS burst since it can't execute 6502 code.
Is it so? Am I stuck with stock CBM speeds whenever I am using ZoomFloppy, even if VICE can emulate various speed loaders?
Anyone any clue?

ZoomFloppy (and all X*1541 cables) use a custom fastloader to speed up the drive. I *think* the Oceanic is enough 1541-like to accept the 1541 fastloader code.

Jim

I can confirm that I can transfer data to/from the OC-118 with CBM Transfer (i.e. with opencbm) at a much faster rate than the stock 1541 speed.
The problem is in VICE. VICE also uses opencbm, but no matter what I do, I can only get the stock transfer rates i.e. utterly slow.
It would be nice to be able to use a real drive with some kind of disk acceleration in VICE.

LoadError wrote:I can confirm that I can transfer data to/from the OC-118 with CBM Transfer (i.e. with opencbm) at a much faster rate than the stock 1541 speed.
The problem is in VICE. VICE also uses opencbm, but no matter what I do, I can only get the stock transfer rates i.e. utterly slow.
It would be nice to be able to use a real drive with some kind of disk acceleration in VICE.

It would be nice, but it's a huge technical challenge to do so. Trying to pass timing sensitive IEC traffic over a different protocol (USB) and then attaching that to the timing sensitive VICE emulator is a wonder that it works at all.

There are still some things that work best using the real HW...

Jim