Raspberry PI SCSI emulator

[Jope]

http://www.geocities.jp/kugimoto0715/rascsi/index.html

Looks interesting, I need to give this a go. :-)

[Codetsu]

Wow this looks really nice 7o7

[Locutus]

....Neat!

C++ Code with Japanese comments....joy :-D

[alexh]

There is a Raspberry Pi powered SCSI emulator for the Atari which can work on Amiga called CosmosEx. Yes it's expensive but good support and good enclosure. Plus it's also a FDDE and keyboard + network adapter

[Pat the Cat]

Little bit skeptical, because very amibitious - looks like doing lots more than usual SD-SCSI adaptor.

It's hard enough doing something that will let you use solid state devices, and Pi3 Model B specified... maybe code done needs that level of processor? I doubt it.

It should not. It is connected to a 25 pin single ended 8 bit SCSI connection, as commonly found on the outside of Amiga SCSI controllers. Typically, that means an extra box with it's own power supply.

Internal fitting, usually it's a 50 pin connector, rarely 68 pin. Not such a straightforward job. Terminating the chain with passive terminators at either end sometimes is not an option, and active termination means the device has to have its own power supply.

http://www.connectworld.net/scsi.html

Here's the bad news - once you fit one SCSI-1 device to a controller, it limits access to all other devices to the same speed. So I understand it anyway, lowest ship in the chain limits the speed of the whole convoy.

It does so much as a solution for many people but it doesn't look ideal to some, from what I understand you can do with Amiga SCSI controllers. Like a Newtek Flyer or better, this sort of device looks questionable connected to that speed of Amiga SCSI controller.

8 bit SCSI is never as fast as 16 bit SCSI. It should work though. Look on the bright side.

[Amiga1992]

Originally Posted by Pat the Cat

Little bit skeptical, because very amibitious - looks like doing lots more than usual SD-SCSI adaptor.

Skeptical of what?
Skeptical of its use in an Amiga? Creator doesn't say that would work (it is an X680x0 expansion after all), but says that the virtual HDD part SHOULD work with other retro devices that use SCSI.

[gulliver]

Originally Posted by Jope

http://www.geocities.jp/kugimoto0715/rascsi/index.html

Looks interesting, I need to give this a go. :-)

Please give it a go and report back with all your findings.

We certainly need this sort of easy and affordable solution for scsi Amigas.

It seems the author gets about 1MB/s performance in read mode, which is much more acceptable than what the SCSI2SD V5 offers.

[idrougge]

Please just ignore Pat the Cat's ramblings.

[McTrinsic]

Originally Posted by gulliver

Please give it a go and report back with all your findings.



We certainly need this sort of easy and affordable solution for scsi Amigas.



It seems the author gets about 1MB/s performance in read mode, which is much more acceptable than what the SCSI2SD V5 offers.

The SCSI2SDv5 _is_ around 1mb/s in my system, a Phoenixboard.

What's the issue?

Cheers,
McT

[gulliver]

Originally Posted by McTrinsic

The SCSI2SDv5 _is_ around 1mb/s in my system, a Phoenixboard.

What's the issue?

Cheers,
McT

Perhaps not in your case, but I get much less than that on my Amiga, besides, it is a much cheaper option. The more options the merrier.

[Pat the Cat]

Originally Posted by Akira

Skeptical of what?
Skeptical of its use in an Amiga? Creator doesn't say that would work (it is an X680x0 expansion after all), but says that the virtual HDD part SHOULD work with other retro devices that use SCSI.

I am sceptical of a device that connects via a 25 pin connector (external SCSI one style) having a complete implementation of SCSI commands as found on Amiga SCSI controllers (usually SCSI-2 fast, sometimes SCSI-2 fast and wide).

It should work as a bare ass drive, in a box, outside of the Amiga, always.

Making sure it always works on the inside of an Amiga is no trivial task, and making it work faster than 5MBS I figure to be an impossible task... but we shall see how builds.

Originally Posted by idrougge

Please just ignore Pat the Cat's ramblings.

A post with zero useful information content in it. Are you volunteering to fix every single one of these units to make them work usable at Flyer speed or better? No. You are just putting up a negative view of me.

Grow up, boy. Real life isn't a playground, try taking some responsibility yourself too.

[McTrinsic]

Originally Posted by gulliver

Perhaps not in your case, but I get much less than that on my Amiga, besides, it is a much cheaper option. The more options the merrier.

Well, it might be that also another solution might not be as fast as expected due to you system?

I mean if the drive can deliver up to 1MB/s but not in you system it might not be due to the drive??

Cheers,
McT

[Daedalus]

Originally Posted by Pat the Cat

I am sceptical of a device that connects via a 25 pin connector (external SCSI one style) having a complete implementation of SCSI commands as found on Amiga SCSI controllers (usually SCSI-2 fast, sometimes SCSI-2 fast and wide).

The connector doesn't always relate to or indicate the type of controller. Of course, you already knew that half the conductors on the 50-pin SCSI-I and SCSI-II ribbon cables aren't active, meaning you only need 25 pins to operate those buses.

It should work as a bare ass drive, in a box, outside of the Amiga, always.

Making sure it always works on the inside of an Amiga is no trivial task,

And which commands exactly are you worried about that would affect an internal drive but not an external drive? I'm curious, because I'm not aware of any... I'm also curious as to how a drive might determine whether it's inside or outside an Amiga. Light sensors? Temperature sensors? Magic?

A post with zero useful information content in it.

Oh, the irony.

[Pat the Cat]

Originally Posted by Daedalus

Of course, you already knew that half the conductors on the 50-pin SCSI-I and SCSI-II ribbon cables aren't active, meaning you only need 25 pins to operate those buses.

Plenty of Amiga owners are unaware of the actual pins used on their SCSI controllers, that's why I posted a link so that people could actually check and see if getting this solution for an internal fitting gives them any advantages.

Usually not, but there are exceptions. Some controllers come with neither a 25 pin nor a 50 pin header, but a 36 pins Centronics connector for an external SCSI drive.

Originally Posted by Daedalus

Of course, you already knew that half the conductors on the 50-pin SCSI-I and SCSI-II ribbon cables aren't active, meaning you only need 25 pins to operate those buses.

Some 50 pin connections do use extra pins, for 16 bit wide SCSI access. Again, that's why I posted the link, so people could check.

Originally Posted by Daedalus

And which commands exactly are you worried about that would affect an internal drive but not an external drive? I'm curious, because I'm not aware of any...

The cause of my concern is HOW WELL IMPLEMENTED the SCSI commands are. Typically an 8 bit SCSI device does not bother, and I respectfully point out that this appears to be a "work in progress" rather than "click here to buy on this website.

Originally Posted by Daedalus

I'm also curious as to how a drive might determine whether it's inside or outside an Amiga. Light sensors? Temperature sensors? Magic?

Actually quite a lot of Amiga and other SCSI controllers simply force 8 bit SCSI if any devices are 8 bit. Connect an 8 bit device to the outside of an Amiga, all the devices inside also get slowed down by 8 bit access.

The Amiga doesn't care, but the user does, if they spent money getting fast controller and then blame the Amiga when a "new" SCSI device makes their drive access slow.

Originally Posted by Daedalus

Oh, the irony.

More trolling. Stay on topic please.

[Daedalus]

Originally Posted by Pat the Cat

... Lots of vague waffle ...

Hmmm, you haven't answered my question. Your previous post makes some "interesting" assertions, I questioned them, and all you've done is waffle vaguely about SCSI without actually answering my query. Please tell us which instructions would cause a drive to always work externally, but be problematic to get working internally. I would also like to know why such instructions would be affected by a 25-pin connector, when Fast SCSI-II can perfectly use such connectors with no difference to throughput or commands used.

More trolling. Stay on topic please.

Nope, just highlighting the obvious irony in your post, but that's more name calling from you...

[Pat the Cat]

OK. 4 questions to be resolved - how well does it handle direct SCSI commands? How well does it switch to synchronous and async operation? How tolerant is it of passive termination or does it demand active termination? Synch and active termination are often hand in hand.

You wanted pure tech gibberish moot questions that may be answered in due time, you got.

One handicap the Pi has is, it can only deal with one pin on the bus at a time, which is maybe why the builder recommends the fastest Pi going. However, one advantage of a Pi zero is, it has far less hardware to take care of, so might end up being quick enough if just doing one task like attaching a drive to an 8 bit port.

However, this project is aimed at doing FAR MORE. It provides network access, CD-ROM image access and MO drive emulation, as well as being a drive. THAT's why I said it's ambitious. Check the site in something closer to English...

https://translate.google.com/transla...tml&edit-text=

[Jeff_HxC2001]

Look at the sources :

http://www.geocities.jp/kugimoto0715.../rascsi120.zip

The target machine seems to need a driver, so this is probably not a pure scsi emulator

[Daedalus]

Originally Posted by Pat the Cat

You wanted pure tech gibberish moot questions that may be answered in due time, you got.

Nope, I didn't. All I wanted was for you to back up your claims, which you didn't.

However, this project is aimed at doing FAR MORE. It provides network access, CD-ROM image access and MO drive emulation, as well as being a drive. THAT's why I said it's ambitious. Check the site in something closer to English...

Indeed, I've already read an approximate translation, and it is an ambitious and impressive project. Forgive me for misunderstanding why you were sceptical. See, when you say things like

I am sceptical of a device that connects via a 25 pin connector (external SCSI one style) having a complete implementation of SCSI commands as found on Amiga SCSI controllers (usually SCSI-2 fast, sometimes SCSI-2 fast and wide).

It should work as a bare ass drive, in a box, outside of the Amiga, always.

Making sure it always works on the inside of an Amiga is no trivial task, and making it work faster than 5MBS I figure to be an impossible task... but we shall see how builds.

it leads people to believe that's the reason you're sceptical. In future, if you say what you actually mean instead of something completed different, you can avoid all this confusion.

[Locutus]

Originally Posted by Jeff_HxC2001

Look at the sources :

http://www.geocities.jp/kugimoto0715.../rascsi120.zip

The target machine seems to need a driver, so this is probably not a pure scsi emulator

I haven't looked very closely (and the japanese docs/comments dont help) but it looks to it implements both block device (fixed, MO) and a SCSI target mode.

Over the SCSI target mode they run some own protocol for ethernet and filesystem level stuff.

I cant be arsed to reply to any of Pat's stuff.

[Zetr0]

@Thread

This is a very interesting project - even more so if its possible to shoe-horn onto a RPi 1 or Zero in the future =)

TCP/IP over SCSI has been around for quite some time. I remember having a play with that atleast 10-15 years ago



@Pat_the_Cat / idrougge / Daedalus

Guys, stop trollin' each other - your better than that.