On 12/05/2020 15:23, Mike Stramba wrote: > What is the "story" with vmb.exe ? > > Is there source code for it ? > > If not, why not ? > > Is it "abandon ware" ? > > I'm interested in seeing how it does "raw disk" access. > > I have MSCP Basic Disk Functions Manual AA-L619A-TK Version 1.2 and > EK-UDA50-UG-002_UDA50_Users_Guide_Oct82.pdf > > Are there any other relevant docs ? >
VMB has different drivers that are invoked for each controller type (MASSBUS, MSCP etc). These drivers are just minimal equivalents of the full drivers within the operating system. Usually they rely on polling rather than using interrupts. Other than that there is nothing particularly special that takes place here. Other documents to look at are: http://www.bitsavers.org/pdf/dec/dsa/mscp/Mass_Storage_Control_Protocol_Ver_2.4.0_Jun92.txt and http://www.bitsavers.org/pdf/dec/disc/uda50/AA-L621A-TK_UnibusPortDescription_1982.pdf In particular look at chapter 4 which describes the command and response rings and chapter 9 which describes the initialisation sequence. Probably the best way to see VMB in action would be to use the debug feature within Simh. I would recommend using the VAX-11/780 simulator for this as VMB is loaded directly after issuing the boot command: sim> set debug stdout sim> set rq debug sim> boot rq0 DBG(5000)> RQ TRACE: rq_reset DBG(5000)> RQ TRACE: rq_clrint Loading boot code from internal vmb.exe DBG(3470473)> RQ TRACE: rq_reset DBG(3470473)> RQ TRACE: rq_clrint Writing to the initialisation/polling register resets the controller: DBG(3483139)> RQ REG: rq_wr(PA=0x2013F468 [IP], access=2, data=0x0000) DBG(3483139)> RQ TRACE: rq_reset DBG(3483139)> RQ TRACE: rq_clrint Values (as described in chapter 9) are written to the status & address register in order to complete the 4 step initialisation sequence: DBG(3483139)> RQ REQ: initialization started DBG(3486350)> RQ REG: rq_rd(PA=0x2013F46A [SA], access=0)=0x0940 DBG(3486357)> RQ REG: rq_wr(PA=0x2013F46A [SA], access=2, data=0x8000) DBG(3486807)> RQ TRACE: rq_quesvc DBG(3486807)> RQ INIT: CSTA=0, SAW=0x8000 DBG(3489569)> RQ REG: rq_rd(PA=0x2013F46A [SA], access=0)=0x1080 DBG(3489576)> RQ REG: rq_wr(PA=0x2013F46A [SA], access=2, data=0xDDD8) DBG(3490026)> RQ TRACE: rq_quesvc DBG(3490026)> RQ INIT: CSTA=2, SAW=0xDDD8 DBG(3492788)> RQ REG: rq_rd(PA=0x2013F46A [SA], access=0)=0x2000 DBG(3492795)> RQ REG: rq_wr(PA=0x2013F46A [SA], access=2, data=0x0003) DBG(3493245)> RQ TRACE: rq_quesvc DBG(3493245)> RQ INIT: CSTA=3, SAW=0x3 DBG(3496007)> RQ REG: rq_rd(PA=0x2013F46A [SA], access=0)=0x4063 DBG(3496014)> RQ REG: rq_wr(PA=0x2013F46A [SA], access=2, data=0x0001) DBG(3496024)> RQ TRACE: rq_quesvc DBG(3496024)> RQ INIT: CSTA=6, SAW=0x1 DBG(3496024)> RQ REQ: initialization complete The initialisation/polling register is read to notify the controller that a new command packet had been placed in the command ring by the host: DBG(3496029)> RQ REG: rq_rd(PA=0x2013F46A [SA], access=0)=0x0000 DBG(3496033)> RQ REG: rq_rd(PA=0x2013F468 [IP], access=0)=0x0000 DBG(3496033)> RQ REQ: poll started, PC=1076 DBG(3496034)> RQ REG: rq_rd(PA=0x2013F46A [SA], access=0)=0x0000 The controller processes a "Set Controller Characteristics" command from the command ring: DBG(3496133)> RQ TRACE: rq_quesvc DBG(3496133)> RQ REQ: cmd=0004(SCC), mod=0000, unit=0, bc=00000000, ma=000000FF, lbn=00000000 DBG(3496133)> RQ TRACE: rq_mscp - Queue DBG(3496133)> RQ TRACE: rq_scc A response packet is placed in the response ring by the controller: DBG(3496133)> RQ REQ: rsp=0084, sts=0000 The initialisation/polling register is read again to notify the controller that a another command packet had been placed in the command ring by the host: DBG(3496148)> RQ REG: rq_rd(PA=0x2013F46A [SA], access=0)=0x0000 DBG(3496152)> RQ REG: rq_rd(PA=0x2013F468 [IP], access=0)=0x0000 DBG(3496152)> RQ REQ: poll started, PC=1076 DBG(3496153)> RQ REG: rq_rd(PA=0x2013F46A [SA], access=0)=0x0000 The controller processes an "Online Drive" command from the command ring: DBG(3496233)> RQ TRACE: rq_quesvc DBG(3496233)> RQ REQ: cmd=0009(ONL), mod=0000, unit=0, bc=00000000, ma=00000000, lbn=00000000 DBG(3496233)> RQ TRACE: rq_mscp - Queue DBG(3496233)> RQ TRACE: rq_onl DBG(3496233)> RQ TRACE: rq_putr_unit A response packet is placed in the response ring by the controller: DBG(3496233)> RQ REQ: rsp=0089, sts=0023 DBG(3496333)> RQ TRACE: rq_quesvc %BOOT-F-Failed to initialize device HALT instruction, PC: 000004C7 (BLBS 549,4C6) The "Online Drive" command fails because no disk image was attached to the device. Matt _______________________________________________ Simh mailing list Simh@trailing-edge.com http://mailman.trailing-edge.com/mailman/listinfo/simh
