Jump to content
K55

RaSCSI Development Thread

Recommended Posts

If I was a better programmer and more versed in programming with these older machines, I would definitely make a powerbook version. Not only be able to emulate a SCSI drive, but emulate a SCSI ethernet (and go over wifi) as well as enable acceleration for WebKit internet browsing. 

Share this post


Link to post
Share on other sites

Here are some benchmarks on Raspberry Pi GPIO performance using DMA:

https://github.com/hzeller/rpi-gpio-dma-demo

 

I read recently of another project running code on the VideoCore to do GPIO, which would allow you to have a separate microcontroller completely dedicated to servicing GPIO.

 

I found this thread on the Raspberry Pi forms referring to the idea:
https://www.raspberrypi.org/forums/viewtopic.php?f=37&t=95572

 

You could achieve a similar thing by isolating one of the cores on the Raspberry Pi 3 from the Linux scheduler and manually pinning your server's IO thread to that core.  

 

https://stackoverflow.com/questions/13583146/whole-one-core-dedicated-to-single-process

Share this post


Link to post
Share on other sites
On 1/23/2018 at 7:25 AM, jamesmilne said:

Raspberry Pi GPIO performance using DMA:

https://github.com/hzeller/rpi-gpio-dma-demo

Quote

Raspberry Pi 1 22.7Mhz, Pi 2 41.7Mhz, Pi 3 65.8 Mhz.

Granted that's toggling a single pin and doing nothing else, but that seems promising.

Does the second example, "Reading Word from memory, write masked set/clr" imply that you can toggle 32 pins at the same speed, or at 1/32 of the speed or worse?

Share this post


Link to post
Share on other sites
On 1/23/2018 at 7:25 AM, jamesmilne said:

running code on the VideoCore / would allow you to have a separate microcontroller completely dedicated to servicing GPIO.

 

Does the GPU have direct access to the GPIO pins?  Or ... could you hijack the camera and MIPI LCD ports for super-fast IO?

Share this post


Link to post
Share on other sites

True, but that involves porting the SCSI emulation to a whole different processor architecture.

Then again, I guess the same applies to trying to run it on the GPU.

Share this post


Link to post
Share on other sites

I'm pretty sure that in theory, probably just about anything you wanted- the problem here is that you'd need to develop a Mac OS driver for each feature (and in some cases, develop an entire stack to support features that had no equivalent, i.e. USB, on classic Mac)

 

Also to clarify, K55 who started this thread was working to make a more accessible Mac-ready hardware kit using the schematics developed by kugimoto0715 (http://www.geocities.jp/kugimoto0715/), I don't think K55 or anyone else here has actually progressed down this route much further- I was originally interested (and have to return to the topic) in using the project to create a multi-game Apple/Bandai/Atmark Pippin game jukebox, as the SCSI2SD has some limitations to this regard that make implementation a bit difficult, but I haven't done any more investigation.

 

On the topic of drivers, kugimoto0715 provides two drivers similar to what you're referring, but for x68000 (one that allows remote file system access, and one that allows the Pi's ethernet to be used directly, but both appear to have been developed through a mixture of already existing software to allow emulators to access their host os.

 

I might look into an updated technically accurate re-translation of the page if no one's poked at it recently, as I see there's some updates since it first went live (I've also seen the compatible adapters for sale in shops such as BEEP recently, so it's no surprise that it's been gaining momentum). curious what this initiator and monitor mode options offer...

Share this post


Link to post
Share on other sites

Hi, I am considering building this adapter. I have a few questions though:

 

1) I would like to build an adapter to connect to the external DB25 SCSI connector of my SE/30, thus should I build the DIN version 1.6d?

2) what is the power connector in the other version for?

3) can I install a male DB25 connector to the port so that I can plug it directly into the Mac?

4) I'm unsure about the resistor networks, due to the "crossed out" pins. What part do I need exactly, and how many pins are used?

5) what should I use as fuse? any specific part suggestion?

6) I gave a quick look at the software side. From what I understand, it is not necessary to install the kernel module, and one can just launch the binary specifying ID and file. correct?

 

Thanks!

Share this post


Link to post
Share on other sites
On 4/14/2018 at 1:30 PM, CRP said:

Hi, I am considering building this adapter. I have a few questions though:

 

1) I would like to build an adapter to connect to the external DB25 SCSI connector of my SE/30, thus should I build the DIN version 1.6d?

2) what is the power connector in the other version for?

3) can I install a male DB25 connector to the port so that I can plug it directly into the Mac?

4) I'm unsure about the resistor networks, due to the "crossed out" pins. What part do I need exactly, and how many pins are used?

5) what should I use as fuse? any specific part suggestion?

6) I gave a quick look at the software side. From what I understand, it is not necessary to install the kernel module, and one can just launch the binary specifying ID and file. correct?

 

Thanks!

Hello!

 

Din would be the outer version yes. The "right" version has a right angle 50 pin scsi for internal use. That's why it has the power connector so you don't have to run a usb cable inside your case if you don't want to, say for a standalone setup.

The db25 pinout should be the same, but I dont know if it would be flush, I couldn't think of a easy way to make it work so I left it as a female jack. The crossed out pin is the silkscreen telling you where the ground pin for the network is. The network will have a dot or a cross to indicate the ground, so you need 9 resistor networks (they have 10 pins :) ). Fuse I left it pretty big to allow you to use anything. I have a parts list @ https://github.com/fran-cap/RASCSI-68kmlaver/blob/master/part information/rascsi_bom.xlsx that might help but any through hole 1A axial fuse should work. The software should work as long as it matches your raspi kernel version.

 

Hope this helps.

Share this post


Link to post
Share on other sites
16 hours ago, K55 said:

Hello!

 

Din would be the outer version yes. The "right" version has a right angle 50 pin scsi for internal use. That's why it has the power connector so you don't have to run a usb cable inside your case if you don't want to, say for a standalone setup.

The db25 pinout should be the same, but I dont know if it would be flush, I couldn't think of a easy way to make it work so I left it as a female jack. The crossed out pin is the silkscreen telling you where the ground pin for the network is. The network will have a dot or a cross to indicate the ground, so you need 9 resistor networks (they have 10 pins :) ). Fuse I left it pretty big to allow you to use anything. I have a parts list @ https://github.com/fran-cap/RASCSI-68kmlaver/blob/master/part information/rascsi_bom.xlsx that might help but any through hole 1A axial fuse should work. The software should work as long as it matches your raspi kernel version.

 

Hope this helps.

Many thanks for the help. I just ordered a couple of din boards on dirtypcb. I shared the pcb, specifying the url of your github page, so everybody can find it there as well. Please let me know if this is ok for you.

I believe I can get all parts at RS online, once the board arrives I will post a complete list of the parts I got and add a posting about how things went with the adapter.

 

Thanks!

Share this post


Link to post
Share on other sites
24 minutes ago, CRP said:

Many thanks for the help. I just ordered a couple of din boards on dirtypcb. I shared the pcb, specifying the url of your github page, so everybody can find it there as well. Please let me know if this is ok for you.

I believe I can get all parts at RS online, once the board arrives I will post a complete list of the parts I got and add a posting about how things went with the adapter.

 

Thanks!

Yes that's fine. Give it a shot. :)

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×