{"id":2060,"date":"2017-06-08T00:03:36","date_gmt":"2017-06-08T00:03:36","guid":{"rendered":"http:\/\/avitech.com.au\/?page_id=2060"},"modified":"2017-06-08T02:01:16","modified_gmt":"2017-06-08T02:01:16","slug":"mfm-hard-drives","status":"publish","type":"page","link":"https:\/\/avitech.com.au\/?page_id=2060","title":{"rendered":"MFM Hard Drives"},"content":{"rendered":"<p>This page is a collection of notes regarding MFM hard drives.<\/p>\n<h4>Drive-Select Jumper Settings<\/h4>\n<p>When using an MFM drive on my RQDX Breakout Board, install link DS1 on the MFM drive.<\/p>\n<p>When using an MFM drive in a DEC BA23 chassis, install link DS3 on the MFM drive (if you install DS1 instead, the MFM Hard Drive and the RX50 Floppy Drive will both respond to the DS1 signal).<\/p>\n<h4>Seagate ST-412<\/h4>\n<p>The specifications for this drive are:<\/p>\n<ul>\n<li>Cylinders: 306<\/li>\n<li>Heads: 4<\/li>\n<li>Sectors\/Track: 17<\/li>\n<li>Precompensation: 128<\/li>\n<li>Landing Zone: 319<\/li>\n<li>Bytes\/Sector: 512<\/li>\n<li>Capacity (formatted): 10MB<\/li>\n<\/ul>\n<p>See <a href=\"http:\/\/stason.org\/TULARC\/pc\/hard-drives-hdd\/seagate\/ST412-10MB-5-25-FH-MFM-ST412.html\" target=\"_blank\">stason.org&#8217;s ST412 page<\/a> for more information about this drive.<\/p>\n<p>Underneath the ST-412 there are two un-populated IC sockets near the 34-way edge connector.<\/p>\n<p>The 14-way IC socket is for the terminating resistor pack. The Pin 1 end of the package is furthest from the edge connector. When tested with a multimeter, the 12 input pins should each measure 138 ohms to Pin 14 and 147 ohms to Pin 7.<\/p>\n<p>The 16-way IC socket is for jumpers (or possibly a dipswitch). It has 8 Options (Jumpers). Option 1 is closest to the 34-way edge connector. The assignment for each Option is as follows:<\/p>\n<ul>\n<li>Option 1: DS1<\/li>\n<li>Option 2: DS2<\/li>\n<li>Option 3: DS3<\/li>\n<li>Option 4: DS4<\/li>\n<li>Option 5: Reserved (leave Closed)<\/li>\n<li>Option 6: Reserved (leave Closed)<\/li>\n<li>Option 7: Reserved (leave Closed)<\/li>\n<li>Option 8: Daisy-Chain (Open) or Radial (Closed). Leave Open<\/li>\n<\/ul>\n<p>Only one of Options 1 through 4 should be Closed.<\/p>\n<p>This drive was used by DEC in the PDP-11 range, designated as an RD51 drive.<\/p>\n<h4>Seagate ST-225<\/h4>\n<p>The specifications for this drive are:<\/p>\n<ul>\n<li>Cylinders: 615<\/li>\n<li>Heads: 4<\/li>\n<li>Sectors\/Track: 17<\/li>\n<li>Precompensation: 300<\/li>\n<li>Landing Zone: 670<\/li>\n<li>Bytes\/Sector: 512<\/li>\n<li>Capacity (formatted): 21MB<\/li>\n<\/ul>\n<p>See <a href=\"http:\/\/stason.org\/TULARC\/pc\/hard-drives-hdd\/seagate\/ST225-21MB-5-25-HH-MFM-ST412.html\" target=\"_blank\">stason.org\u2019s ST225 page<\/a> for more information about this drive<\/p>\n<p>The last drive must have a terminating resistor pack fitted. This is a single-in-line package that plugs in underneath the PCB.<\/p>\n<p>The manual for the ST-225 is <a href=\"http:\/\/www.avitech.com.au\/mm-files\/mfm-drives\/Seagate%20ST225%20OEM%20Manual%201985.pdf\" target=\"_blank\">available here<\/a>.<\/p>\n<p>The configuration jumpers are on the back of the ST-225. From left to right they are:<\/p>\n<ul>\n<li>Pins 15-16: DS1<\/li>\n<li>Pins 13-14: DS2<\/li>\n<li>Pins 11-12: DS3<\/li>\n<li>Pins 9-10: DS4<\/li>\n<li>Pins 7-8: Life Test (leave Open)<\/li>\n<li>Pins 5-6: Write Fault (leave Open)<\/li>\n<li>Pins 3-4: Recovery Mode (leave Open)<\/li>\n<li>Pins 1-2: Radial (leave Open)<\/li>\n<\/ul>\n<p>Only one of DS1 through DS4 should be Closed.<\/p>\n<p>This drive was used by DEC in the PDP-11 range, designated as an RD31 drive.<\/p>\n<h4>Seagate ST-4053<\/h4>\n<p>The specifications for this drive are:<\/p>\n<ul>\n<li>Cylinders: 1024<\/li>\n<li>Heads: 5<\/li>\n<li>Sectors\/Track: 17<\/li>\n<li>Precompensation: N\/A (1025)<\/li>\n<li>Landing Zone: N\/A (Auto Park)<\/li>\n<li>Bytes\/Sector: 512<\/li>\n<li>Capacity (formatted): 44MB<\/li>\n<\/ul>\n<p>More information about this drive is available at:<\/p>\n<ul>\n<li><a href=\"http:\/\/stason.org\/TULARC\/pc\/hard-drives-hdd\/seagate\/ST4053-45MB-5-25-FH-MFM-ST412.html\" target=\"_blank\">stason.org\u2019s ST4053 page<\/a><\/li>\n<li><a href=\"ftp:\/\/ftp.seagate.com\/techsuppt\/mfm\/st4053.txt\" target=\"_blank\">Seagate&#8217;s ST4053 page<\/a><\/li>\n<\/ul>\n<p>The configuration jumpers are on the back of the ST-4053. They are physically in the same location as appears on the ST-225, but the pin numbering is different.  From left to right they are:<\/p>\n<ul>\n<li>Pins 1-2: DS1<\/li>\n<li>Pins 3-4: DS2<\/li>\n<li>Pins 5-6: DS3<\/li>\n<li>Pins 7-8: DS4<\/li>\n<li>Pins 9-10: <unknown> (leave Open)<\/li>\n<li>Pins 11-12: Write Fault. Stason.org&#8217;s page says this should be Closed, but I leave Open<\/li>\n<li>Pins 13-14: Recovery Mode. Stason.org&#8217;s page says this should be Closed, but I leave Open<\/li>\n<li>Pins 15-16: Daisy-Chain \/ Radial (leave Open, for Daisy Chain)<\/li>\n<\/ul>\n<p>Only one of DS1 through DS4 should be Closed.<\/p>\n<p>The ST-4053 was not used on DEC&#8217;s PDP-11 MFM controllers (eg RQDX3), but can be used on the PDP-11 with Webster&#8217;s SRQD11 controller.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>This page is a collection of notes regarding MFM hard drives. Drive-Select Jumper Settings When using an MFM drive on my RQDX Breakout Board, install link DS1 on the MFM drive. When using an MFM drive in a DEC BA23 chassis, install link DS3 on the MFM drive (if you install DS1 instead, the MFM ..<\/p>\n<div class=\"clear-fix\"><\/div>\n<p><a href=\"https:\/\/avitech.com.au\/?page_id=2060\" title=\"read more...\">Read more<\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-2060","page","type-page","status-publish","hentry"],"jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/P7xTsk-xe","jetpack-related-posts":[{"id":1524,"url":"https:\/\/avitech.com.au\/?page_id=1524","url_meta":{"origin":2060,"position":0},"title":"MFM Hard Drive on Pentium II PC","author":"malcolm","date":"7-January-2017","format":false,"excerpt":"The \"older\" PCs that I have laying around in the workshop all tend to be Pentium II era machines or later. Unfortunately I don't have much in the way of working 8086, 286, 386 or 486 PCs. The Pentium 2 machines work just fine for me for almost all of\u2026","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2017\/01\/drive-and-controller-cropped-300x215.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":645,"url":"https:\/\/avitech.com.au\/?page_id=645","url_meta":{"origin":2060,"position":1},"title":"RQDX Breakout Board","author":"malcolm","date":"28-June-2016","format":false,"excerpt":"Quick Links Feel free to click on one of the links in this section to jump to the material you are looking for: Introduction \u00a0 Quickstart Guide \u00a0 Floppy Drives \u00a0 Hard Drives \u00a0 Miscellaneous \u00a0 Downloads \u00a0 Table of Contents \u00a0 Contact Details Introduction DEC made a series of\u2026","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"rqdx3-cropped","src":"https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2016\/06\/rqdx3-cropped-300x175.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":2402,"url":"https:\/\/avitech.com.au\/?page_id=2402","url_meta":{"origin":2060,"position":2},"title":"RQDX Mini-BOB for floppy drives","author":"malcolm","date":"27-July-2017","format":false,"excerpt":"This simple PCB will enable one or two 3.5\" or 5.25\" floppy drives to be directly connected to a PDP-11 RQDX-series controller. It is a simplified version of my earlier RQDX Breakout Board. Unlike my earlier board, this board will not connect to an MFM hard drive, and does not\u2026","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2017\/07\/populated-pcb-1024-440-300x129.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":1840,"url":"https:\/\/avitech.com.au\/?page_id=1840","url_meta":{"origin":2060,"position":3},"title":"Konan Blue Sky MFM Controller","author":"malcolm","date":"17-April-2017","format":false,"excerpt":"I have a \"Blue Sky\" Konan MFM controller board in an SD Systems S-100 machine. The MFM hardware consists of: \"Blue Sky\" single-sided PCB, plugged in to the Z-80 socket on the SBC-200 CPU board A Konan external PCB fitted with a large \"Konan\" branded LSI chip Disctron D-507 5MB\u2026","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2017\/04\/20170417_142539_1492406887735_resized-e1492432436254.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2017\/04\/20170417_142539_1492406887735_resized-e1492432436254.jpg?resize=350%2C200 1x, https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2017\/04\/20170417_142539_1492406887735_resized-e1492432436254.jpg?resize=525%2C300 1.5x, https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2017\/04\/20170417_142539_1492406887735_resized-e1492432436254.jpg?resize=700%2C400 2x, https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2017\/04\/20170417_142539_1492406887735_resized-e1492432436254.jpg?resize=1050%2C600 3x, https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2017\/04\/20170417_142539_1492406887735_resized-e1492432436254.jpg?resize=1400%2C800 4x"},"classes":[]},{"id":807,"url":"https:\/\/avitech.com.au\/?page_id=807","url_meta":{"origin":2060,"position":4},"title":"Webster SRQD11","author":"malcolm","date":"22-July-2016","format":false,"excerpt":"This page is about a PDP-11 QBUS non-DEC MFM Winchester Disc Controller that I really like: the Webster SRQD11-A. The SRQD11 is similar in some ways to DEC's family of RQDX controllers. Both boards are \"dual-height\" QBUS boards, and both can be used to connect an MFM hard drive to\u2026","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2016\/07\/srqd11-and-drive.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2016\/07\/srqd11-and-drive.jpg?resize=350%2C200 1x, https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2016\/07\/srqd11-and-drive.jpg?resize=525%2C300 1.5x, https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2016\/07\/srqd11-and-drive.jpg?resize=700%2C400 2x, https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2016\/07\/srqd11-and-drive.jpg?resize=1050%2C600 3x, https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2016\/07\/srqd11-and-drive.jpg?resize=1400%2C800 4x"},"classes":[]},{"id":1552,"url":"https:\/\/avitech.com.au\/?page_id=1552","url_meta":{"origin":2060,"position":5},"title":"VAXmate","author":"malcolm","date":"8-January-2017","format":false,"excerpt":"The VAXmate is an IBM PC\/AT compatible personal computer produced by DEC. Its claim to fame is that it is the world's first commercially produced diskless (ie net-booting) personal computer, as discussed on on the VAXmate's Wikipedia and Microsoft webpages. But it can also be used as a standalone conventional\u2026","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2017\/01\/20170108_192644_1483864602434_resized-1.jpg?resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2017\/01\/20170108_192644_1483864602434_resized-1.jpg?resize=350%2C200 1x, https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2017\/01\/20170108_192644_1483864602434_resized-1.jpg?resize=525%2C300 1.5x, https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2017\/01\/20170108_192644_1483864602434_resized-1.jpg?resize=700%2C400 2x, https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2017\/01\/20170108_192644_1483864602434_resized-1.jpg?resize=1050%2C600 3x, https:\/\/i0.wp.com\/avitech.com.au\/wp-content\/uploads\/2017\/01\/20170108_192644_1483864602434_resized-1.jpg?resize=1400%2C800 4x"},"classes":[]}],"_links":{"self":[{"href":"https:\/\/avitech.com.au\/index.php?rest_route=\/wp\/v2\/pages\/2060","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/avitech.com.au\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/avitech.com.au\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/avitech.com.au\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/avitech.com.au\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2060"}],"version-history":[{"count":8,"href":"https:\/\/avitech.com.au\/index.php?rest_route=\/wp\/v2\/pages\/2060\/revisions"}],"predecessor-version":[{"id":2070,"href":"https:\/\/avitech.com.au\/index.php?rest_route=\/wp\/v2\/pages\/2060\/revisions\/2070"}],"wp:attachment":[{"href":"https:\/\/avitech.com.au\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2060"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}