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Tandy 1000EX found at surplus dealer

by jwest＠classiccmp.org

TSIA, let me know if someone wants me to inquire about price. J

9 years, 10 months

Looking for a particular 5.25" floppy drive - Epson SD521

by shadoooo＠gmail.com

Hello Adrian, if the head positioning motor works, but the drive simply doesn't read the data, maybe the problem is in some track misalignment or bad head signal amplification / A/D conversion. Don't know about these drives, but if the interface is pretty standard, you could try the correct operation of the positioning motor simply powering the drive setting the signal DIRECTION high or low, and giving pulses to the STEP signal. You can do it connecting simple wires between 5V and GND and the pins on the connector on the back. The positioning motor should move back and forth in steps. For the track-0 sensor simply use a multimeter / oscilloscope and check if the level changes when the head is in track-0 position. For the READ signal the thing is more difficult, because you need an oscilloscope to check the fast changing signals. You can check for good looking output signal, without spurious pulses or bad edges. Then you possibly have to check for correct timings, and this is even more difficult, but doable with the right equipment (powerful oscilloscope). Some drives have a small trimmer to slightly correct the spindle motor speed, whence the timing. Alignment can be corrected loosening slightly the blocking screws between the head carriage and the stepper motor moving it, or in some drive the screws holding the stepper to the chassis frame, and moving head carriage / stepper motor very slowly in both directions until the amplitude of the signal of the read head is at the maximum. Then lock again the screws. Years ago I had to repair four floppy drives for two DG One machines, as they were all failing, not reading nor formatting. Spindle rotated well, head moved correctly, but the drives couldn't read disks, and not even re-read its own data (formatting), hence something bad on read / write circuits. After various tests, the problem was on bad electrolytic capacitors on the spindle board. As the spindle motor started, it emitted high current pulses that caused ripple on the supply and also induced spurious pulses on the analog read signal. Result, the read data was badly interfered, and of course not correctly interpreted by the controller. I changed the capacitors, 3 over 4 drives worked. The last one required head alignment, but I didn't have any alignment disk. So I wrote three test disks with the 3 working drives, and tried to align the 4th to the best match. Then finally even the 4th worked! If you are in willing to try something, let me know. Andrea

9 years, 10 months

WTB TRS-80 CoCo Orchestra 90 Cartridge

by nf6x＠nf6x.net

I'm looking for an Orchestra 90 cartridge for my CoCos. Does anybody have an extra for sale or trade? -- Mark J. Blair, NF6X <nf6x at nf6x.net> http://www.nf6x.net/

9 years, 10 months

VT2xx simulation with SIMH

by aek＠bitsavers.org

Related to the RT-11 discussion, there is currently work going on to have a simulated VT240 in MAME working with RT-11 running in SIMH. http://forums.bannister.org/ubbthreads.php?ubb=showflat&Number=106655#Post1…

9 years, 10 months

Looking for a particular 5.25" floppy drive - Epson SD521

by witchy＠binarydinosaurs.co.uk

Hi folks, This a long shot but worth an ask. Has anyone got a pair of Epson SD521 5.25" drives going spare? I have two in a Memotech FDX disk subsystem that appear to have gone south on me, and while I can swap out for any other DS/DD drive it'd be nice restore it using original spares. The SD521 is an odd beast since it doesn't have a slide or lever to engage the heads, it's all done on a push button. These ones are aware there's a disk inserted and will home the heads if manually pulled forwards, but seeking doesn't work. Maybe the track0 sensor? Cheers! -- Adrian/Witchy Binary Dinosaurs creator/curator Www.binarydinosaurs.co.uk - the UK's biggest private home computer collection?

9 years, 10 months

[SPAM key] - Re: memory map for RT-11 v 5

by jhfinedp3k＠compsys.to

>On Sunday, July 24th, 2016 at 14::29:59 -0700, Don North wrote: > >On 7/24/2016 8:06 AM, william degnan wrote: > >> >On Jul 24, 2016 8:58 AM, "Jerome H. Fine" <jhfinedp3k at compsys.to> >> wrote: >> >>>> >On Wednesday, July 20th, 2016 at 18:02:44 - 0400, william degnan >>>> wrote: >>>> Is there a minimum memory requirement for RT-11 v5? I was >>>> discussing with >>> >>>> Ray Fantini about it today, unsure...anyone know if 16K will work >>>> (from >>>> 000000). >>>> >>>> Bill >>>> >>> You need to be more specific! Starting with V05.00 of RT-11 in 1983, >>> there were a total of 17 versions released up to V05.07 in 1998, >>> including >>> sub-versions V05.01B, V05.01C, and V05.04A to V05.04G of RT-11. >>> >>> Up until V05.05 of RT-11, RT11SJ.SYS required the least memory which >>> was replaced with RT11SB.SYS for V05.06 and V05.07 of RT-11. >>> >>> Attempts to boot from RT11SJ.SYS under V05.00 of RT-11 with 24K >>> bytes of memory were successful. Attempts to boot with 16K bytes of >>> memory were unsuccessful. An RK05 was used as the disk drive since >>> it is close to the smallest device driver. The answer to your question >>> about using 16K bytes of memory is NO for all versions of RT-11 >>> starting with >>> V05.00 or RT-11. >>> >>> Attempts to boot from RT11SJ.SYS under V04.00 of RT-11 with 24K >>> bytes of memory were successful. Attempts to boot with 16K bytes of >>> memory were also successful. An RK05 was used as the disk drive. The >>> error message "Insufficient memory" is displayed, but some useful work >>> might be done with just 16K bytes of memory. However, you did not >>> ask if useful work being done was one of the criteria? >>> >>> NOTE that I used the Ersatz-11 emulator to check the above details, >>> so there might be a difference with actual hardware. >>> >>> If you have any more questions, please ask. >>> >>> Jerome Fine >> >> Thanks for the details. I had been trying to boot rt-11 v5.3 on a >> 16k core >> 11/40 using RL11 (rl02) and it did not work. The system was unable to >> complete the initialization. CPU diagnostics passed, I could load BASIC >> papertape. RL11 working correctly. In this context I posted my >> question. >> >> After I posted my message here I loaded up simh and emulated an 11 with >> 32k. RT-11 v5.3 disk boots. When I re-built the system and reduced to >> 16k, I could not boot, bombed. >> >> One thing to remember is 16KW in a pdp11 is not the same thing that simh >> refers to when one sets the CPU to 16K. WWW do not all make this >> distinction clearly. I get it, just making this comment for future >> readers >> of this thread. >> >> Bill > > > RT-11 v5.03 single job monitor boots fine and runs in just 32KB (16KW) > of memory. > > You need to be more specific about how you specify the memory > configuration (words vs bytes). > > DEC routinely specified everything in KW (words) but most users and > tools use KB (bytes) nowadays. > > Note that to force RT11SJ (vs RT11FB) to boot on the below image I > booted first using FB > in a larger memory configuration, did a: > > COPY/BOOT DL1:RT11SJ.SYS DL1: > > to force it to boot using the SJ monitor the next time. NOTE that while the above command is REQUIRED to perform a hardware boot (from boot ROMs on real hardware or from within the SimH emulator. Starting at least with V04.00 of RT-11, a software boot (which uses DUP.SAV) is supported from within RT-11 from within any disk (with the files required to support being a System Disk) to boot any specific monitor file (in this example RT11SJ.SYS) using the RT-11 command: BOOT DL1:RT11SJ Thus even if there has been the RT-11 command to set up a boot block on a specific disk for a specific RT-11 monitor file, it is possible to override the boot block and use any qualified RT-11 monitor file via an RT-11 software boot (which uses DUP.SAV). It is also possible from within RT-11 to force the use of the Primary Boot Code (which is placed in block zero via the COPY/BOOT command) via the RT-11 command: BOOT/FOREIGN DL1: If the user includes a specific monitor in the command: BOOT/FOREIGN DL1:RT11FB then the specified monitor file is ignored and the boot code in block zero of DL1: (placed there via the COPY/BOOT command) is used instead along with the actual monitor file that had been specified during the COPY/BOOT command. > > Don > > > PDP-11 simulator V4.0-0 Beta git commit id: 4065f47f This portion of my reply contains many questions. If possible, answers to all of them would be appreciated, not just the first question. Is this the latest version of SimH? Also, is is possible to support a VT100 display. I have heard that telnet can be used, but I have never been able to do so. Since I always use the RT-11 SL: (Single Line Editor) device driver to support a command stack, it is essential to support a VT100 display, etc. in order to use the ARROW keys to move the cursor around. Is it possible to support VT100 escape sequences when SimH is being used? If so, how is that done in general and what specific programs are required along with the specific commands to implement? I would need to know how to do this from a 64-bit Windows 10 point of view since that is the only system that I will have available after the Windows 98SE system that I currently use to run RT-11 is no longer available. As a default, Ersatz-11 supports running via the Win32 variant under a 64-bit Windows 10 system. > > CPU 11/34, FPP, idle disabled, autoconfiguration enabled > 32KB > > NOTE: ctrl-E to exit to SIMH monitor > sim> boot rl1 > > RT-11SJ (S) V05.03 > > .sho all If I remember correctly, the above RT-11 command may be incorrect. I seem to remember that the following output is displayed as a result of the RT-11 command: SHOW CONFIGURATION unless, of course, the rest of the display was omitted and there was much more actually output. > > RT-11SJ (S) V05.03 > Booted from DL1:RT11SJ > > USR is set SWAP > EXIT is set SWAP > KMON is set NOIND > TT is set NOQUIET > ERROR is set ERROR > SL is set OFF > EDIT is set KED > KMON nesting depth is 3 > > PDP 11/34 Processor > 32KB of memory > FP11 Hardware Floating Point Unit > Extended Instruction Set (EIS) > Memory Management Unit > 60 Cycle System Clock Jerome Fine

9 years, 10 months

memory map for RT-11 v 5

by jhfinedp3k＠compsys.to

I forgot to remove the "Spam Key" notice that my ISP puts into most of my e-mail when I replied the first time - I apologize!!! >On Sunday, July 24th, 2016 at 14::29:59 -0700, Don North wrote: > >On 7/24/2016 8:06 AM, william degnan wrote: > >> >On Jul 24, 2016 8:58 AM, "Jerome H. Fine" <jhfinedp3k at compsys.to> >> wrote: >> >>>> On Wednesday, July 20th, 2016 at 18:02:44 - 0400, william degnan >>>> wrote: >>>> Is there a minimum memory requirement for RT-11 v5? I was >>>> discussing with >>> >>>> Ray Fantini about it today, unsure...anyone know if 16K will work >>>> (from >>>> 000000). >>>> >>>> Bill >>>> >>> You need to be more specific! Starting with V05.00 of RT-11 in 1983, >>> there were a total of 17 versions released up to V05.07 in 1998, >>> including >>> sub-versions V05.01B, V05.01C, and V05.04A to V05.04G of RT-11. >>> >>> Up until V05.05 of RT-11, RT11SJ.SYS required the least memory which >>> was replaced with RT11SB.SYS for V05.06 and V05.07 of RT-11. >>> >>> Attempts to boot from RT11SJ.SYS under V05.00 of RT-11 with 24K >>> bytes of memory were successful. Attempts to boot with 16K bytes of >>> memory were unsuccessful. An RK05 was used as the disk drive since >>> it is close to the smallest device driver. The answer to your question >>> about using 16K bytes of memory is NO for all versions of RT-11 >>> starting with >>> V05.00 or RT-11. >>> >>> Attempts to boot from RT11SJ.SYS under V04.00 of RT-11 with 24K >>> bytes of memory were successful. Attempts to boot with 16K bytes of >>> memory were also successful. An RK05 was used as the disk drive. The >>> error message "Insufficient memory" is displayed, but some useful work >>> might be done with just 16K bytes of memory. However, you did not >>> ask if useful work being done was one of the criteria? >>> >>> NOTE that I used the Ersatz-11 emulator to check the above details, >>> so there might be a difference with actual hardware. >>> >>> If you have any more questions, please ask. >>> >>> Jerome Fine >> >> Thanks for the details. I had been trying to boot rt-11 v5.3 on a >> 16k core >> 11/40 using RL11 (rl02) and it did not work. The system was unable to >> complete the initialization. CPU diagnostics passed, I could load BASIC >> papertape. RL11 working correctly. In this context I posted my >> question. >> >> After I posted my message here I loaded up simh and emulated an 11 with >> 32k. RT-11 v5.3 disk boots. When I re-built the system and reduced to >> 16k, I could not boot, bombed. >> >> One thing to remember is 16KW in a pdp11 is not the same thing that simh >> refers to when one sets the CPU to 16K. WWW do not all make this >> distinction clearly. I get it, just making this comment for future >> readers >> of this thread. >> >> Bill > > RT-11 v5.03 single job monitor boots fine and runs in just 32KB (16KW) > of memory. > > You need to be more specific about how you specify the memory > configuration (words vs bytes). > > DEC routinely specified everything in KW (words) but most users and > tools use KB (bytes) nowadays. > > Note that to force RT11SJ (vs RT11FB) to boot on the below image I > booted first using FB > in a larger memory configuration, did a: > > COPY/BOOT DL1:RT11SJ.SYS DL1: > > to force it to boot using the SJ monitor the next time. > > Don NOTE that while the above command is REQUIRED to perform a hardware boot (from boot ROMs on real hardware or from within the SimH emulator. Starting at least with V04.00 of RT-11, a software boot (which uses DUP.SAV) is supported from within RT-11 from within any disk (with the files required to support being a System Disk) to boot any specific monitor file (in this example RT11SJ.SYS) using the RT-11 command: BOOT DL1:RT11SJ Thus even if there has been the RT-11 command to set up a boot block on a specific disk for a specific RT-11 monitor file, it is possible to override the boot block and use any qualified RT-11 monitor file via an RT-11 software boot (which uses DUP.SAV). It is also possible from within RT-11 to force the use of the Primary Boot Code (which is placed in block zero via the COPY/BOOT command) via the RT-11 command: BOOT/FOREIGN DL1: If the user includes a specific monitor in the command: BOOT/FOREIGN DL1:RT11FB then the specified monitor file is ignored and the boot code in block zero of DL1: (placed there via the COPY/BOOT command) is used instead along with the actual monitor file that had been specified during the COPY/BOOT command. > PDP-11 simulator V4.0-0 Beta git commit id: 4065f47f This portion of my reply contains many questions. If possible, answers to all of them would be appreciated, not just the first question. Is this the latest version of SimH? Also, is is possible to support a VT100 display. I have heard that telnet can be used, but I have never been able to do so. Since I always use the RT-11 SL: (Single Line Editor) device driver to support a command stack, it is essential to support a VT100 display, etc. in order to use the ARROW keys to move the cursor around. Is it possible to support VT100 escape sequences when SimH is being used? If so, how is that done in general and what specific programs are required along with the specific commands to implement? I would need to know how to do this from a 64-bit Windows 10 point of view since that is the only system that I will have available after the Windows 98SE system that I currently use to run RT-11 is no longer available. As a default, Ersatz-11 supports running via the Win32 variant under a 64-bit Windows 10 system. > CPU 11/34, FPP, idle disabled, autoconfiguration enabled > 32KB > > NOTE: ctrl-E to exit to SIMH monitor > sim> boot rl1 > > RT-11SJ (S) V05.03 > > .sho all If I remember correctly, the above RT-11 command may be incorrect. I seem to remember that the following output is displayed as a result of the RT-11 command: SHOW CONFIGURATION unless, of course, the rest of the display was omitted and there was much more actually output. > RT-11SJ (S) V05.03 > Booted from DL1:RT11SJ > > USR is set SWAP > EXIT is set SWAP > KMON is set NOIND > TT is set NOQUIET > ERROR is set ERROR > SL is set OFF > EDIT is set KED > KMON nesting depth is 3 > > PDP 11/34 Processor > 32KB of memory > FP11 Hardware Floating Point Unit > Extended Instruction Set (EIS) > Memory Management Unit > 60 Cycle System Clock Jerome Fine

9 years, 10 months

more vintage computer stuff

by sales＠elecplus.com

Another fellow is slimming his warehouse. There are 4 pallets, and I have a spreadsheet. Every item has been tested, and there are comments, from "Works OK" to "loud noise and smells burnt". Primarily old Apple gear, but there are also 2 NIB Tandon TM848-E 8" floppy drives. If you want to see the spreadsheet and the pics, send me an email. Cindy Croxton Electronics Plus 500 Pershing Ave. Kerrville, TX 78028 830-370-3239 cell sales at elecplus.com AOL IM elcpls

9 years, 10 months

Intel 432 floppy flux images for decoding

by drb＠msu.edu

A collection of intel floppies containing software related to the 432 processor was identified and purchased by Nigel Williams. I made flux images of the diskettes some time ago, but have failed to assemble the attention span to decode most of them. Technical details: These are 8" diskettes, written in several different formats. There are FM and M2FM, and possibly MFM, floppies. The flux images were created using a DiscFerret board. Three flux image files were created from each diskette, at three sampling rates: 25, 50 and 100 MHz. (This is certainly overkill, but I wasn't sure what would end up working best.) Both sides were imaged, and the reader software was told to take two passes over each track. The FM diskettes are SSSD, with 128 byte sectors. (The FM ones are already mostly decoded.) For each floppy, a photo of the label, a text transcription of the label, and the three .dfi image files are available. The files are available here: http://www.kb8zqz.net/intelfloppies/ Documentation of the .dfi file format is here: http://www.discferret.com/wiki/DFI_image_format I'm available (drb at msu.edu) to try to answer questions about the imaging process. Nigel and I hope that this might lie close enough to someone's interests to attract some tuits. De

9 years, 10 months

IBM 3511

by cctalk＠ibm51xx.net

Pictures or it didn'didn't happen ;) -Ali -------- Original message -------- From: William Donzelli <wdonzelli at gmail.com> Date: 6/9/2016 10:39 PM (GMT-05:00) To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> Subject: IBM 3511 So today I picked up something I had never seen before - an IBM 3511. This is a large tower expansion chassis for the PS/2 line. It looks very straightforward - but can any of you PS/2 fans comment on this? Was it an unsuccessful product? Low demand item? -- Will

9 years, 10 months

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