From: Michael L. Umbricht [mikeu@starfish.osfn.org] Sent: Monday, March 04, 2002 7:45 AM To: Info-VAX@Mvb.Saic.Com Subject: Re: DEC Professional 300 series FAQ I am taking on the editing and maintaining of the DEC Pro FAQ. (I contacted Chaim R. Dworkin, the originator of the FAQ, and he doesn't mind) I have started by creating a Part IV to extend the original 3 part faq, and will go back to edit the first 3 parts later. The new Q&A are included below. The most recent version of the new faq (and some additional information) may be found at: http://starfish.rcsri.org/rcs/pdp-11/Professional/ There is also an archived copy of the 1994 version of the FAQ there. Please feel free to send comments, contributions and suggestions to me at mikeu@starfish.rcsri.org Followup-To: comp.sys.dec.micro -mikeu Retro-Computing Society of RI http://www.osfn.org/rcs/ ================================ DEC Professional Computer Frequently Asked Questions and Miscellaneous Trivia ================================ Currently maintained by: Michael Umbricht mikeu@starfish.rcsri.org Originally compiled and edited by: Chaim Dworkin chaim@linc.cis.upenn.edu ------------------------------------------------------------------------------ Vol. 4 No. 1 Part IV Size:113 lines; 4623 bytes 2 Mar, 2002 ------------------------------------------------------------------------------ This is Part 4 of a 4 part post. This "FAQ and other miscellaneous trivia" is compiled from discussions which took place on comp.sys.dec.micro over the past years. Whenever possible names and addresses of contributing individuals are placed after each answer. Additions, corrections, and constructive comments are welcomed. This FAQ was originated, compiled and edited by Chaim Dworkin. The original version of this FAQ (dated 5 May, 1994) is archived at: http://starfish.rcsri.org/rcs/pdp-11/Professional/faq/old This file is an addendum to the above mentioned three part FAQ. It is currently maintained by Michael Umbricht The most recent version may found at: http://starfish.rcsri.org/rcs/pdp-11/Professional/faq/ Summary of questions in this Addendum: Q44. Why do SHOW MEMORY and Configuration Display sometimes report different sizes for memory? Q45. What is the CP/M Option Module? Q46. What is the ID number? Q47. What is the CTI bus? ************************** Q44. Why do SHOW MEMORY and Configuration Display sometimes report different sizes for memory? For example: the PRO/Tool Kit command SHOW MEMORY reports 320k (words) yet the Maintenance Services Configuration Display reports 512 kilobytes of memory (system total) The difference between the two is due to the presence of a DECNA card which has 128Kbytes of RAM. This memory is not just used as buffer space for Ethernet packets; the memory is dual-ported and can be accessed by the CPU and other devices on the bus. Maintenance Services does not appear to "count" this memory, but it is seen and used by P/OS. ************************** Q45. What is the CP/M Option Module? The CP/M Option consists of hardware and software: a CTI card (000043) which contains a Z80-A microprocessor, 64Kbytes of RAM, 4Kbytes of ROM and CP/M-80 which runs on top of P/OS. P/OS can continue to multitask in the background while CP/M is running. CP/M-format diskettes (96 tpi) can be read or written in the RX50 drive, 48tpi diskette can be read only, and up to four virtual diskettes can be accessed on the hard disk. A CP/M application can also read P/OS sequential files allowing data exchange between the two. CP/M does not have access to the Pro's hardware registers, so applications (such as graphics) that have been written for specific I/O devices will not work. Applications that use CP/M services for I/O will run without modification. The DEC order code is PC3XS-AA There are three diskettes: BL-V447B-BH Pro CP/M-80 APP DSKT V1.1 (1983) BL-AH67A-BH PRO-CP/M-80 APPLICATION (1983) DISKETTE SYSTEM V1.1 BL-V448B-BH PRO-CP/M-80 APPLICATION (1983) DISKETTE HARD DISK SYSTEM V1.1 ************************** Q46. What is the ID number? Each Pro has a 47-bit Identification number stored in ROM. This is not the same as the serial number printed on the case label. Some software (for instance VENIX) is keyed to this number. To view the ID use Maintenance Services and choose Configuration Display. The top line shows: Identification number: ############ ************************** Q47. What is the CTI bus? The Pro system bus is called the CTI, or Computing Terminals Interconnect bus. It has 22-bit addressing (4Mbytes) and multiplexes addresses and data, combining 16-bit data signals with the 22-bit address signals on 22 signal lines. In most cases, the bus will allow option modules to be placed in any available option slot. Each option module can generate two different hardware interrupt signals. The option modules feature zero-insertion force connectors. When an option is in place, an option-present signal is asserted. Each option contains onboard ROM with identification information. ************************** End of File