matthew180 Posted July 1, 2013 Share Posted July 1, 2013 Since I never had a hard disk for my 99/4A PEB, can someone give me the break-down on how they were implemented from a hardware perspective as well as software support? I assume the controller has a CRU that it responds to and provides a ROM-based DSR? But what about directory support, how was that done? And how does a hard disk look to environments like XB or games that load saved games, etc? Quote Link to comment https://forums.atariage.com/topic/214044-994a-hard-disk/ Share on other sites More sharing options...
Opry99er Posted July 1, 2013 Share Posted July 1, 2013 Just for clarification, you are not referring to a RAMDisk, correct? Quote Link to comment https://forums.atariage.com/topic/214044-994a-hard-disk/#findComment-2784666 Share on other sites More sharing options...
matthew180 Posted July 1, 2013 Author Share Posted July 1, 2013 Nope, no a RAMDisk. But if those were set up to work like a hard disk, then info on those would be nice too. I think there were hard disk controllers for the 99/4A though, with disk sizes well beyond what you could get in a RAM disk of the day. Quote Link to comment https://forums.atariage.com/topic/214044-994a-hard-disk/#findComment-2784677 Share on other sites More sharing options...
Opry99er Posted July 1, 2013 Share Posted July 1, 2013 AHH, ok. I know a bit about the HRD, but I know very little about the Myarc HFDC. But many out there do.... Shame Richard Bell isn't active here often. He would be the guy... Michael Zapf and Jim Fetzner also excellent resources. The list goes on. Quote Link to comment https://forums.atariage.com/topic/214044-994a-hard-disk/#findComment-2784683 Share on other sites More sharing options...
marc.hull Posted July 1, 2013 Share Posted July 1, 2013 (edited) Since I never had a hard disk for my 99/4A PEB, can someone give me the break-down on how they were implemented from a hardware perspective as well as software support? I assume the controller has a CRU that it responds to and provides a ROM-based DSR? But what about directory support, how was that done? And how does a hard disk look to environments like XB or games that load saved games, etc? Tim will jump in and give you an in depth but in short a hard disk (MFM, SCSI IDE for the TI) looks and works just like any other device except the directory is included in the device name IE the device SCS1.EA5.GAMES.PACMAN Would look for the file PACMAN in SCSi disk 1 in directory EA5 and in sub directory GAMES. The DSR (controlled by CRU) does the heavy lifting. OLD IDE1.XBGAMES.CONTEST.LUNAR Is a valid statement that causes the DSR to seek and load the file that it finds in the directory tree. It's seamless Any disk cat routine can be easily modified to search devices and directories by just adding on to the device name. Only caveat is the total device and file name can be no more than 40 characters (I'm pretty sure) including the dots. Tim will correct me if I am wrong but the directory structure is saved on the device so any DSR must have the ability to load that info and parse it. Edited July 1, 2013 by marc.hull Quote Link to comment https://forums.atariage.com/topic/214044-994a-hard-disk/#findComment-2784695 Share on other sites More sharing options...
+InsaneMultitasker Posted July 1, 2013 Share Posted July 1, 2013 The Myarc HFDC manual documents the disk structures for both a floppy and hard drive device fairly well. As Marc points out the subdirectory structure is a major difference. The internal structure of a hard drive is very similar to that of a floppy. Where it differs is the subprograms used for lower level disk access and the manner in which the bitmap, FDR, and pointers are stored to account for the larger medium. Like most peripheral cards it responds to a CRU base address, contains a DSR ROM (16K) banked in 4K chunks, and a standard 8k (expandable to 32K) RAM chip for buffers windowed in three 1K chunks. The SCSI and IDE cards handle their DSRs and memory mapping differently, but ultimately they utilize a similar structure. The IDE DSR allows for up to 4 partitions per each of the two drives. The SCSI and MFM drives do not allow partitions and only operate on physical devices (in the case of SCSI, some can be mapped to logical units). Programs such as terminal emulators, disk managers, and any program performing IO beyond level 3 (that is, open/read/write/close/delete/load/save) operations requires more work and extra programming. The catalog function Marc refers to works the same but accounts for folders and emulation images, so you can catalog a hard drive from BASIC/XB or assembly fairly easily. The Myarc, SCSI, and IDE DSRs also allow for the buffers and peripheral access blocks to be located within CPU RAM space. The TI and CorComp can only access buffers and PABs within VDP. So where the TI must first load disk data into VDP RAM, then copy to CPU for various tasks, the newer card DSRs were written to go directly to/from CPU, speeding IO operations. There is a lot more out there and I'm sure others on this forum can and might chime in. I just tried to cover some of the main topics that might complement Marc's post. Quote Link to comment https://forums.atariage.com/topic/214044-994a-hard-disk/#findComment-2784700 Share on other sites More sharing options...
RXB Posted July 1, 2013 Share Posted July 1, 2013 Since I never had a hard disk for my 99/4A PEB, can someone give me the break-down on how they were implemented from a hardware perspective as well as software support? I assume the controller has a CRU that it responds to and provides a ROM-based DSR? But what about directory support, how was that done? And how does a hard disk look to environments like XB or games that load saved games, etc? I still have my SCSI card in my Pbox and it and the SAMS are the only cards I have never had a issue with. Quote Link to comment https://forums.atariage.com/topic/214044-994a-hard-disk/#findComment-2784765 Share on other sites More sharing options...
RXB Posted July 1, 2013 Share Posted July 1, 2013 The IDE DSR allows for up to 4 partitions per each of the two drives. The SCSI and MFM drives do not allow partitions and only operate on physical devices (in the case of SCSI, some can be mapped to logical units). Programs such as terminal emulators, disk managers, and any program performing IO beyond level 3 (that is, open/read/write/close/delete/load/save) operations requires more work and extra programming. The catalog function Marc refers to works the same but accounts for folders and emulation images, so you can catalog a hard drive from BASIC/XB or assembly fairly easily. The Myarc, SCSI, and IDE DSRs also allow for the buffers and peripheral access blocks to be located within CPU RAM space. The TI and CorComp can only access buffers and PABs within VDP. So where the TI must first load disk data into VDP RAM, then copy to CPU for various tasks, the newer card DSRs were written to go directly to/from CPU, speeding IO operations. SCSI is way better then the Myarc HFDC. SCSI and Myarc HFDC had much in common but size of the drive is larger for the SCSI card. RXB has built in CALL SCSI for a query of the SCSI card. Also a XB program that shows what it does. RXB can do CATalog or DIRectory or COPY or RENAME or PROTECT or MaKDIRectories or ReMove DIRectories or multiple remove directories with CUTDIR or SECTOR Hard drives like the Myarc or SCSI. RXB has not been tested on a IDE but if it works on both the SCSI and HFDC I imagine it sould work on any hard drive with the same set ups. Quote Link to comment https://forums.atariage.com/topic/214044-994a-hard-disk/#findComment-2784770 Share on other sites More sharing options...
RobertLM78 Posted July 1, 2013 Share Posted July 1, 2013 Is anyone producing PEB HD controller cards anymore? Quote Link to comment https://forums.atariage.com/topic/214044-994a-hard-disk/#findComment-2784782 Share on other sites More sharing options...
Gazoo Posted July 1, 2013 Share Posted July 1, 2013 (edited) Something not mentioned that I and others have recently implemented is the use of a Compact Flash card in place of a hard drive using the SCSI card. You get a SCSI to IDE adapter, an IDE to Compact Flash adapter, daisy chain them all together and you've got a 248mb flash drive for your TI or Geneve. The Geneve will boot from it, too. I've got both my TI and Geneve set up like I described, and can't imagine life without them. Transfers from the PC are incredibly easy, too. Take the CF card to the PC and dump it to a binary file. Use TiImageTool to read or write files on the file, and write the file back to the CF card if you've written to it. It's especially useful when using MESS, you can have the exact same hard drive on real and emulated systems and work on either without worrying about getting things transferred back and forth. Gazoo Edited July 1, 2013 by Gazoo 1 Quote Link to comment https://forums.atariage.com/topic/214044-994a-hard-disk/#findComment-2785098 Share on other sites More sharing options...
RobertLM78 Posted July 1, 2013 Share Posted July 1, 2013 Something not mentioned that I and others have recently implemented is the use of a Compact Flash card in place of a hard drive using the SCSI card. You get a SCSI to IDE adapter, an IDE to Compact Flash adapter, daisy chain them all together and you've got a 248mb flash drive for your TI or Geneve. Sounds fairly intense - does there happen to be a tutorial out there on doing that? You'd still have to have a SCSI card, for the TI I'd reckon, too... Quote Link to comment https://forums.atariage.com/topic/214044-994a-hard-disk/#findComment-2785115 Share on other sites More sharing options...
Gazoo Posted July 1, 2013 Share Posted July 1, 2013 Sounds fairly intense - does there happen to be a tutorial out there on doing that? You'd still have to have a SCSI card, for the TI I'd reckon, too... Not intense at all, fairly simple. just plug everything in. The most difficult part is setting the jumpers on the SCSI to IDE adapter, but you can just look at Marc's website for the settings. Gazoo Quote Link to comment https://forums.atariage.com/topic/214044-994a-hard-disk/#findComment-2785142 Share on other sites More sharing options...
RXB Posted July 1, 2013 Share Posted July 1, 2013 Something not mentioned that I and others have recently implemented is the use of a Compact Flash card in place of a hard drive using the SCSI card. You get a SCSI to IDE adapter, an IDE to Compact Flash adapter, daisy chain them all together and you've got a 248mb flash drive for your TI or Geneve. The Geneve will boot from it, too. I've got both my TI and Geneve set up like I described, and can't imagine life without them. Transfers from the PC are incredibly easy, too. Take the CF card to the PC and dump it to a binary file. Use TiImageTool to read or write files on the file, and write the file back to the CF card if you've written to it. It's especially useful when using MESS, you can have the exact same hard drive on real and emulated systems and work on either without worrying about getting things transferred back and forth. Gazoo GREAT IDEA! Quote Link to comment https://forums.atariage.com/topic/214044-994a-hard-disk/#findComment-2785144 Share on other sites More sharing options...
mnbvcxz Posted July 1, 2013 Share Posted July 1, 2013 Sounds fairly intense - does there happen to be a tutorial out there on doing that? You'd still have to have a SCSI card, for the TI I'd reckon, too... You could probably do the same thing with a CF7/Nano-peb. Quote Link to comment https://forums.atariage.com/topic/214044-994a-hard-disk/#findComment-2785177 Share on other sites More sharing options...
matthew180 Posted July 2, 2013 Author Share Posted July 2, 2013 @Marc and Tim. Thanks for the technical breakdown. A few questions come to mind when I read through it all. What is the max hard drive size you can use, and what creates that limit? Also, wouldn't environments like XB still put its disk buffers in VRAM? Finally, I don't think the CF7 acts like a hard disk does it? More like a really big floppy drive? 1 Quote Link to comment https://forums.atariage.com/topic/214044-994a-hard-disk/#findComment-2785228 Share on other sites More sharing options...
Gazoo Posted July 2, 2013 Share Posted July 2, 2013 (edited) @Marc and Tim. Thanks for the technical breakdown. A few questions come to mind when I read through it all. What is the max hard drive size you can use, and what creates that limit? 248 mb. Space restrictions for bitmap Also, wouldn't environments like XB still put its disk buffers in VRAM? Yes, but if using assembly, you can use RAM. Finally, I don't think the CF7 acts like a hard disk does it? More like a really big floppy drive? From my understanding, it's a collection of floppy disk images on a mass storage device that can be paged in to act like floppies. You can have 3 paged in at a time to act as DSK1, DSK2, & DSK3. So no, not a really big floppy, but a lot of regualar sized ones that you can only use 3 at a time. Gazoo Edited July 2, 2013 by Gazoo Quote Link to comment https://forums.atariage.com/topic/214044-994a-hard-disk/#findComment-2785241 Share on other sites More sharing options...
+acadiel Posted July 2, 2013 Share Posted July 2, 2013 Not intense at all, fairly simple. just plug everything in. The most difficult part is setting the jumpers on the SCSI to IDE adapter, but you can just look at Marc's website for the settings. Gazoo Yep. I used a 512MB in mine but only partitioned the max available. I have pictures on hexbus.com (start with this one and look at the next few.): http://hexbus.com/TI-99_4A_Home_Computer_Page/Hardware_Projects.html#44 Quote Link to comment https://forums.atariage.com/topic/214044-994a-hard-disk/#findComment-2785301 Share on other sites More sharing options...
marc.hull Posted July 2, 2013 Share Posted July 2, 2013 Is anyone producing PEB HD controller cards anymore? A while back James was toying with and may have started (I can't remember) a redraw of the IDE card using through hole parts instead of surface mounted ones (chief complaint it seems.) Didn't get much traction or support here but maybe times have changed. Here is the link to the old thread... http://atariage.com/forums/topic/178360-ide-card/ It's out of date but perhaps worth bringing back from the dead ? Quote Link to comment https://forums.atariage.com/topic/214044-994a-hard-disk/#findComment-2785318 Share on other sites More sharing options...
+Vorticon Posted July 2, 2013 Share Posted July 2, 2013 A while back James was toying with and may have started (I can't remember) a redraw of the IDE card using through hole parts instead of surface mounted ones (chief complaint it seems.) Didn't get much traction or support here but maybe times have changed. Here is the link to the old thread... http://atariage.com/...78360-ide-card/ It's out of date but perhaps worth bringing back from the dead ? I would love a through the hole IDE card. The SMD parts are the source of endless headaches with intermittent contacts and such. Who do I send the check to 1 Quote Link to comment https://forums.atariage.com/topic/214044-994a-hard-disk/#findComment-2785362 Share on other sites More sharing options...
RobertLM78 Posted July 2, 2013 Share Posted July 2, 2013 A while back James was toying with and may have started (I can't remember) a redraw of the IDE card using through hole parts instead of surface mounted ones (chief complaint it seems.) Didn't get much traction or support here but maybe times have changed. Here is the link to the old thread... http://atariage.com/...78360-ide-card/ It's out of date but perhaps worth bringing back from the dead ? I'd say definitely worth bringing back from the dead - an HD controller card something I've wanted for a few years now (IDE , SCSI, SATA, I don't care, as long as I can have a hard drive instead of playing the 5.25" disk swap ) . Quote Link to comment https://forums.atariage.com/topic/214044-994a-hard-disk/#findComment-2785395 Share on other sites More sharing options...
Willsy Posted July 2, 2013 Share Posted July 2, 2013 Count me in! Quote Link to comment https://forums.atariage.com/topic/214044-994a-hard-disk/#findComment-2785445 Share on other sites More sharing options...
RXB Posted July 2, 2013 Share Posted July 2, 2013 The new standard is going to be Serial SAS that uses the same plugs as the SATA drive. Serial SAS is way faster then anything else but nice to see SCSI making a come back. Quote Link to comment https://forums.atariage.com/topic/214044-994a-hard-disk/#findComment-2785448 Share on other sites More sharing options...
Willsy Posted July 2, 2013 Share Posted July 2, 2013 While we're talking about this stuff: What options would I have for my SGCPU system? I have a fully-loaded SGCPU system from Michael Becker, complete with SCSI card. However, I don't really want to run a SCSI drive. I'd rather run an SD card on the end of the drive cable. Is it possible to get some sort of SCSI<-->SD converter? Quote Link to comment https://forums.atariage.com/topic/214044-994a-hard-disk/#findComment-2785478 Share on other sites More sharing options...
Willsy Posted July 2, 2013 Share Posted July 2, 2013 http://www.vintage-computer.com/vcforum/showthread.php?22906-SCSI-1-to-from-IDE-drive-converter/page13&highlight=scsi2ide (scroll down to the last entry for a status update) Quote Link to comment https://forums.atariage.com/topic/214044-994a-hard-disk/#findComment-2785481 Share on other sites More sharing options...
Gazoo Posted July 2, 2013 Share Posted July 2, 2013 While we're talking about this stuff: What options would I have for my SGCPU system? I have a fully-loaded SGCPU system from Michael Becker, complete with SCSI card. However, I don't really want to run a SCSI drive. I'd rather run an SD card on the end of the drive cable. Is it possible to get some sort of SCSI<-->SD converter? Look at message 10 in this thread. You can substitute the IDE to Compact Flash converter with an IDE to SD converter. Gazoo Quote Link to comment https://forums.atariage.com/topic/214044-994a-hard-disk/#findComment-2785482 Share on other sites More sharing options...
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