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DREM FDD/HDD Emulator


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#51 BeeryMiller ONLINE  

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Posted Thu Sep 6, 2018 6:16 PM

Well, the DREM is now working with two hard disk images on a TI-99/4A.  I have not added the other unit to the Geneve yet as I need to backup some files first on the Geneve.  Likely to be done sometime this weekend as time permits.

 

There were two issues with the last issue I mentioned above.  One, I had one line in a CFG file that needed to be removed, and another line that needed to be added.  Also, turns out there was a malloc issue with memory I apparently uncovered that is being fixed with an update in a few minutes.

 

I am right now formatting a 1024 cylinder, 16 head, 32 sector per track image.  My attempt to use a MAME HD image stripped of the header was initially unsuccessful.  Not sure if this is tied to the malloc issue and will allow easy migration between the two systems or not.

 

Ksarul (or anyone else with a DREM), write to me at beery at USWingNuts dot com and I will be happy to share the binary files and appropriate cfg files to get you up and going.  

 

The one thing I am up in the air about at the moment is mounting the DREM.  I thought it would mount as is in a 3.5" floppy drive mount that goes into a 5.25" bay.  The mount I have will not work due to some chip locations on the back of the card.  I am trying to find out if there is a recommended mount other than what I have that is suitable.  Then, I will be able to have 2 hard drives and a floppy drive in m PEBox.  

 

Beery



#52 RickyDean ONLINE  

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Posted Fri Sep 7, 2018 5:51 AM

:thumbsup: Drool!!, Drool!! :thumbsup:   :grin:



#53 BeeryMiller ONLINE  

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Posted Sat Sep 8, 2018 12:47 PM

Been learning some limitations to the HFDC and DREM.

 

I've always thought the HFDC by default could support 16 heads.  Nope, it is 8 heads, unless you do a Barry Boone modification that was published in Micropendium.

 

I've got a good 40 MB image of the contents of my existing MFM hard drive on the Geneve and will be moving things across sometime in the next few  hours.  Once I connect it to my Geneve, I will be able to assemble some source files to confirm the MDM5 copying process was good.  Spot checks displaying source files have thus far been good.

 

Trying to create a 8 head x 32 sectors/track, 1024 cylinder image at the moment.

 

The DREM does some caching before writing to the SD card, and using two large capacity drives may be exceeding some of the onboard memory that created some issues I was experiencing.  After I get this single large image created, I am going to limit myself to that one drive on each system.

 

Beery

 



#54 BeeryMiller ONLINE  

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Posted Sun Sep 9, 2018 6:40 PM

Well, I got the DREM attached to my Myarc HFDC in my Geneve system.  I would say everything is working as it should at the 99% level.

 

The only issue I have come across is in a dual hard drive emulation where one drive may "time out" if it is accessed after a lot of work has been done on the other drive.  At present, I have 2 x 40 MB drives being emulated.

The only time I saw the above issue is when I do a COPY Filepath\* to the current path.  MDOS attempts to buffer as many files in memory before it writes to the other path.  After the files are written and it goes back to the input path for more files, it sometimes comes back with a device error because of the timeout.  Using Clint Pulley's Directory Manager and I had no problem. 

 

I was able to use Mike Maksimik's CFORM as well from MDOS to format an image besides using MDM5 on the TI-99/4A.  It does report "ECC Errors" and attempts to fix them with Mike's CFORM.  When all was said and done, it had a good image.

 

Anyways, more testing as I seek out the optimum drive size (largest suitable for use) for a single drive setup.  Most of the last bit of work was identifying the various commands that needed to be either implemented as "default" in the HDC9234 cfg file to resolve the various nuances between all the MFM controllers out there.

 

If you need something to replace an aging MFM drive, this is the route to go.

 

Beery

 



#55 sparkdrummer OFFLINE  

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Posted Sun Sep 9, 2018 8:00 PM

My trigger finger is getting itchy to pull for my second TI-99/4A system. I sssume it will work well with it?

#56 BeeryMiller ONLINE  

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Posted Sun Sep 9, 2018 8:10 PM

My trigger finger is getting itchy to pull for my second TI-99/4A system. I sssume it will work well with it?

 

I have seen no issues with a single drive.  With dual drive images, there is a timeout issue with the way it handles the cache that is an annoyance.

 

The DREM is advertised as having a future of using both emulated floppies and hard drive images simultaneously.  I have not tested any floppies yet.  I suspect there may be a bit of trial and error to get the settings right for it as well.

 

Users getting one should get an all plastic 3.5" housing for a 5.25" drive bay.  They are available for about $5 and will need some #6 plastic screws for mounting in the plastic housing.  I picked some #6 plastic screws up at Ace Hardware.

 

Beery



#57 BeeryMiller ONLINE  

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Posted Mon Sep 10, 2018 7:34 AM

Oleksandr sent me another update late last night.  This latest update appears to have resolved the timeout issues I was describing earlier.  I am now formatting a 128 MB image at 8 heads, 2048 cylinders, 32 sectors/cylinder.  On the DREM side, things are progressing well without errors. CFORM is going to take probably a couple of hours to finish this up.

 

Also, with last night's update, hard drive speed is now faster than the real hardware.  Previously, it took 80 seconds to assemble and save an image of a program I have on real hardware.  It now takes 60 seconds.

 

Beery



#58 BeeryMiller ONLINE  

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Posted Tue Sep 11, 2018 8:58 AM

And as of about 9 pm last night, Oleksandr chased down and fixed the timeout issue.  I am successfully running 40 MB hard drive images without issue now.

 

Beery



#59 BeeryMiller ONLINE  

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Posted Wed Sep 12, 2018 5:14 AM

At this point, I am not aware of any issues with the DREM and use as emulating a MFM drive on the TI-99/4A.  MDM5 last night formatted a 8 head by 1024 cylinder by 32 sector per cylinder image (64 MB) and an 8 head by 2048 by 32 sector per cylinder image (128 MB) without issue with the DREM emulator.  I've now got over 500,000 sectors free on the 128 MB image.

 

I was using two MFM images for drive 1 and drive 2 without issue.

 

I will take the 128 MB image tonight, make a copy, and do testing on the Geneve 9640 with two images.

 

Things look good.

 

Ksarul, not sure if you have been in contact with Oleksandr or not.  If you need copies of the updated bin files or copies of formatted images, or all the cfg options I have setup, let me know.  Oleksandr can be reached at info@drem.info 

 

I know I am using some config options he added I know was not in the original manual.  He has been updating the online manual, just not sure where it is with the recent changes of the past few days.

 

Beery



#60 BeeryMiller ONLINE  

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Posted Thu Oct 4, 2018 12:29 PM

I need to follow-up with some additional information on the DREM.

 

Most of my use has been with the Geneve 9640.  I have two DREM's, one for the TI-99/4A, and another for the Geneve.

 

Initial work with the TI-99/4A looked liked things were good.  With the Geneve 9640, I am experiencing an issue I am still trying to chase down.

 

Nothing is causing data corruption.  Rather, at times, a file can not be saved or a file loaded from the command line.  I've noticed this during the assembly process working with source files.  Sometimes, I get a file just can not be found, or a Media Error is reported back.  I think it has something to do with a read or a write not being ready, but it does not quite make sense since the DREM has shown to be faster than a regular hard drive.

 

It appears to be some kind of timing issue and I just have not been able to place my finger on what setting(s) may need to be modified.  Oleksandr has indicated I may need to tie some lines to a reset line.  I'm not totally convinced of this, but he is more familiar.  He has a drawing for the TI-99/4A, but nothing for the Geneve 9640.

 

Is there someplace on the Geneve I would be able to pick up this line that is used for the TI-99/4A?  I hate to consider running a special wire in the PEBox special for the Geneve, so perhaps I can pickup a line off of the HFDC instead accomplishing the same thing?

 

Feedback is welcome.

 

 

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#61 BeeryMiller ONLINE  

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Posted Mon Oct 8, 2018 4:53 PM

I believe Oleksandr has got the issues resolved I was experiencing.  He went back to some test machines and identified some timing issues that were different between a 256 byte sector versus a 512 byte typically used on MFM drives and tweaked some gap times, and it appears all is well now.

 

I did not to add any special reset circuitry.  I do note one must turn on the DREM first, and give it 10 seconds or so to boot its OS and begin caching some cylinders.  Once that is done, it appears to be good.

 

Beery



#62 Ksarul OFFLINE  

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Posted Mon Oct 8, 2018 5:21 PM

Looks like I need to get the software to update mine. . .thanks for being the guinea pig on this one, Beery!



#63 BeeryMiller ONLINE  

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Posted Tue Oct 9, 2018 5:08 AM

I sent you a private message with the two updated files.  One needs to be renamed as Atariage would not allow a bit file extension.

 

I was giving the updates a pretty good workout last night and never had a fault.  The one thing I have seen is that the DREM needs to cache some cylinders first before turning on the Geneve.  It is not much more different than turning on a hard drive first, just the DREM needs a bit more time to be ready.  Oleksandr is looking for a Reset Input line on the Geneve from some schematics to address that minor annoyance.  

 

It took some time to get everything worked out, but the payoff is nice.  Glad to be able to not rely upon some old MFM hard drives where you wonder if the next time you turn them on if they will not spin up, etc.

 

Beery



#64 mizapf OFFLINE  

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Posted Tue Oct 9, 2018 6:01 AM

The one thing I have seen is that the DREM needs to cache some cylinders first before turning on the Geneve.  It is not much more different than turning on a hard drive first, just the DREM needs a bit more time to be ready.

 

In fact, I had a quite similar problem in MAME when I implemented the ST-225 emulation. According to the specs, the drive required some time for spinning up, and I implemented that by a delay, after which the drive announed READY. Unfortunately, the Geneve already attempted to boot from it and gave up. At this point I had to realize that this won't be easy to emulate, since there is only one turn-on action in MAME, that is, by starting the driver. There is nothing like doing some preparation work before (maybe some day). In the end I shortened the spinup time so that the Geneve did not complain anymore. Also, I noticed there are some HFDCs that have another switch to turn on the "HD1 wait".



#65 BeeryMiller ONLINE  

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Posted Tue Oct 9, 2018 6:23 AM

 

In fact, I had a quite similar problem in MAME when I implemented the ST-225 emulation. According to the specs, the drive required some time for spinning up, and I implemented that by a delay, after which the drive announed READY. Unfortunately, the Geneve already attempted to boot from it and gave up. At this point I had to realize that this won't be easy to emulate, since there is only one turn-on action in MAME, that is, by starting the driver. There is nothing like doing some preparation work before (maybe some day). In the end I shortened the spinup time so that the Geneve did not complain anymore. Also, I noticed there are some HFDCs that have another switch to turn on the "HD1 wait".

 

Does anyone know what that modification is for the HD wait? Source? Would like to give that information to Oleksandr since it is a tested option.

 

Beery



#66 Ksarul OFFLINE  

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Posted Tue Oct 9, 2018 8:40 AM

Wasn't that HD1 Wait switch there so that the computer would NOT wait for the HD (and would then assume it was not present) so that the startup time would be a lot faster when the card was being used in FDC-only mode?



#67 RickyDean ONLINE  

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Posted Tue Oct 9, 2018 9:25 AM

This sounds so good. I do have a question that would not deter me from buying, but do you know Beery, if this would support two or more HD images being accessed at once. Say hook up more than one twenty pin data connector from the HFDC and use two seperate HD images or all three, even if the last is read only. I believe this would really be a bonus. If you bought just two yet could read 6 images on two HFDC's. Just thinking out loud.  :-D  :)  :-D



#68 mizapf OFFLINE  

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Posted Tue Oct 9, 2018 9:26 AM

According to the HFDC manual, the switch is queried by CRU bit 3, active high, and is named "Wait for HD1 ready". This implies that off means "don't wait". I guess this also means there are differences in the DSR (checking the switch or not).



#69 BeeryMiller ONLINE  

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Posted Tue Oct 9, 2018 10:07 AM

This sounds so good. I do have a question that would not deter me from buying, but do you know Beery, if this would support two or more HD images being accessed at once. Say hook up more than one twenty pin data connector from the HFDC and use two seperate HD images or all three, even if the last is read only. I believe this would really be a bonus. If you bought just two yet could read 6 images on two HFDC's. Just thinking out loud.  :-D  :)  :-D

 

A single HFDC supports three hard drives for read, but only the first two for read/write.  For a TI-99/4A, I would presume one could probably edit the DSR and change WDS1/WDS2/WDS3 to WDS4/WDS5/WDS6 and have two HFDC's in the system.  To my knowledge, that has never been done.

 

I am not precisely sure by what you mean accessing two HD images "at once".  If you mean having two images, the DREM already supports having drive WDS1/HDS1 and WDS2/HDS2.  There is not a third connector on the DREM for the 20 pin cable for the third drive.  There is not anything stopping someone from having a long 34 pin cable to use the first two drives on the DREM, and then the third drive at the end for the read only hard drive and attaching the 20 pin cable on the third port on the HFDC to the third drive.

 

Myself, I am using a 40 MB hard drive image for my drive one.  When I first started testing for Oleksandr, I had a second cable image/drive I was emulating as well.  To resolve issues, Oleksandr suggested I use only one drive initially.  Since things look like they are resolved on that front, I will likely add a second image this evening.

 

I did have some complications with some large 80 and 128 MB images when we first started working out the kinks.  I actually need to see/test if those images now work with out issues.  if they do, one could conceivably have about 256 MB of online storage.  The DREM had some onboard memory for caching, but it did not have enough memory to cache that much online storage.  

 

Beery



#70 RickyDean ONLINE  

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Posted Tue Oct 9, 2018 10:29 AM

 

 

I am not precisely sure by what you mean accessing two HD images "at once".  If you mean having two images, the DREM already supports having drive WDS1/HDS1 and WDS2/HDS2.  There is not a third connector on the DREM for the 20 pin cable for the third drive.  There is not anything stopping someone from having a long 34 pin cable to use the first two drives on the DREM, and then the third drive at the end for the read only hard drive and attaching the 20 pin cable on the third port on the HFDC to the third drive.

 

 

This answers my wish, I think you misunderstood, I have two HFDC's, one for one Geneve and one for another, there would not be two in on system. Will this be usable with a personality card at all? Thanks



#71 BeeryMiller ONLINE  

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Posted Tue Oct 9, 2018 11:24 AM

This answers my wish, I think you misunderstood, I have two HFDC's, one for one Geneve and one for another, there would not be two in on system. Will this be usable with a personality card at all? Thanks

 

Ricky, you will need to investigate what kind of controller chip the personality card is equipped and compare it to what is listed for the DREM on their website.  What I can say is that the specific format for the 9234 chip will not be the format you specifically need for the personality card.   It isl likely something else may get you started in the right direction, but whether there is a drop in placement, I can not answer as I just do not know.  If you have the controller chip manual and specs, you could shoot Oleksandr an email at info at drem dot net and he can probably answer your question.

 

Beery






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