{"id":26197630,"url":"https://github.com/hackerb9/tribology","last_synced_at":"2026-02-18T18:32:17.092Z","repository":{"id":271059420,"uuid":"910781466","full_name":"hackerb9/tribology","owner":"hackerb9","description":"The Trouble With (amateur) Tribology for the Apple II floppy drive","archived":false,"fork":false,"pushed_at":"2025-01-24T07:07:25.000Z","size":338,"stargazers_count":0,"open_issues_count":2,"forks_count":0,"subscribers_count":1,"default_branch":"main","last_synced_at":"2025-10-12T18:49:25.439Z","etag":null,"topics":[],"latest_commit_sha":null,"homepage":null,"language":"BASIC","has_issues":true,"has_wiki":null,"has_pages":null,"mirror_url":null,"source_name":null,"license":null,"status":null,"scm":"git","pull_requests_enabled":true,"icon_url":"https://github.com/hackerb9.png","metadata":{"files":{"readme":"README.md","changelog":null,"contributing":null,"funding":null,"license":null,"code_of_conduct":null,"threat_model":null,"audit":null,"citation":null,"codeowners":null,"security":null,"support":null,"governance":null,"roadmap":null,"authors":null,"dei":null,"publiccode":null,"codemeta":null,"zenodo":null}},"created_at":"2025-01-01T12:07:39.000Z","updated_at":"2025-01-24T07:07:28.000Z","dependencies_parsed_at":"2025-01-05T07:23:49.805Z","dependency_job_id":"98bc0d51-5eec-4e8f-98c5-3cf8291634c1","html_url":"https://github.com/hackerb9/tribology","commit_stats":null,"previous_names":["hackerb9/tribology"],"tags_count":0,"template":false,"template_full_name":null,"purl":"pkg:github/hackerb9/tribology","repository_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/hackerb9%2Ftribology","tags_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/hackerb9%2Ftribology/tags","releases_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/hackerb9%2Ftribology/releases","manifests_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/hackerb9%2Ftribology/manifests","owner_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners/hackerb9","download_url":"https://codeload.github.com/hackerb9/tribology/tar.gz/refs/heads/main","sbom_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/hackerb9%2Ftribology/sbom","scorecard":null,"host":{"name":"GitHub","url":"https://github.com","kind":"github","repositories_count":286080680,"owners_count":29589524,"icon_url":"https://github.com/github.png","version":null,"created_at":"2022-05-30T11:31:42.601Z","updated_at":"2026-02-18T16:55:40.614Z","status":"ssl_error","status_checked_at":"2026-02-18T16:55:37.558Z","response_time":162,"last_error":"SSL_connect returned=1 errno=0 peeraddr=140.82.121.6:443 state=error: unexpected eof while reading","robots_txt_status":"success","robots_txt_updated_at":"2025-07-24T06:49:26.215Z","robots_txt_url":"https://github.com/robots.txt","online":false,"can_crawl_api":true,"host_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub","repositories_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories","repository_names_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repository_names","owners_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners"}},"keywords":[],"created_at":"2025-03-12T02:48:17.754Z","updated_at":"2026-02-18T18:32:17.069Z","avatar_url":"https://github.com/hackerb9.png","language":"BASIC","funding_links":[],"categories":[],"sub_categories":[],"readme":"# The Trouble With (amateur) Tribology\n\nThis repository is for investigating how floppy disks wear down\nso that the hobbyists, curators, and retro-computer archaeologists\ncan keep these beasts from the dawn of the computer-age alive\nas best they can with what materials are now available.\n\n## Motivation\n\nCurrently there is a lack of \ninformation about the correct replacement for the felt \npressure pad seen in single-sided disk drives used in\nearly microcomputers. The pad pushes \nthe rotating diskette against the read/write head\nand there is a possibility that using the wrong material can lead\nto a disk wearing out prematurely, especially if they \nare used as \"flippy\" disks.[^1] \n\n[^1]: \"Flippy disks\" are disks that have a write-protect hole punched in them by \nthe end user so that they can be flipped over and both sides used \nin a single-sided drive. Some pundits claim that\nflippy disks will \nwear out the head because the disk will rotate backwards, spewing\nout the accumulated particles trapped in the filter material.\n\nAt the time the drives were made (late 1970s to early 1980s), \nprofessional research into the  wear properties was limited\nbecause floppy disks were abundant and one could just buy\nreplacement pads from the manufacturer. (Shugart recommendeded\ndoing so every 10,000 hours, if I recall correctly). \n\nThere are plenty of anecdotal stories of substitute materials \npeople have used that \"work\" to allow the drive to read and write,\nbut no information about which materials cause the least damage to magnetic media.\n\nThe hope is that by releasing a program which can make testing\neasier, those who care about such things will be inspired to\nrun tests and share the results. As the most commonly available single-sided\ndrive was the Drive II used in the Apple II line of computers, [this\nprogram](TRIBOLOGY.bas) is written in Applesoft BASIC for a system running \nApple's DOS 3.3.\n\n## Usage\n\nIn order to test a component, use the TRIBOLOGY TRIAL program which\nprompts for a track to move the head to and then cycles around on it\nforever, perhaps scraping off the magnetic material and etching a ring\ninto the diskette. \n\nAn ideal test will run for 7 days straight. (Shugart says there should be\nno damage to the media from the pad or head after 3 × 10⁶ revolutions). \nHowever, visible evidence of damage has been appearing in less than 24 hours.\n\n\n## Limitations\n\n* The program attempts to calculate elapsed wall time but it is not very\naccurate, so it's better to use an external clock when possible. For reasons\nnot clear to me, the speed of my timing loop depends upon whether\nit is run automatically as the Apple II \"HELLO\" program or from the prompt.\n\n* The best metric for evaluation is not yet clear. Perhaps the ideal would be for the test rig to automatically compare the signal level on the track before and after the test. However, the disk controller does not make that information available to the Apple II and so multimeter or oscilloscope may be necessary. For now, visual estimates are being used along with minimal verification that the data has not been corrupted.\n\n## Test results\n\n### 0: Old (original?) felt pad in a Drive II\n\n| | |\n|-----|-----|\n|Origin| Likely originally shipped with the Apple Drive II |\n| Material | Synthetic (melts instead of burning) |\n| Filament length | Short | \n| Density | Firmly packed, coloration is yellowish brown, probably from age. |\n| Notes| The floppy disk used in this test was not new, unlike the other tests. This also used a different drive mechanism.| \n\n#### Trial 0-A\n\n| | |\n|-|-|\n| Test duration | \u003e24 hours |\n| Testing method | [TRIBOLOGY.bas](TRIBOLOGY.bas) |\n| Track # (of 40) | 12 |\n| Test summary | **Pass** |\n\nResults: No noticeable difference. However, concentric rings at every track are visible under a microscope, so perhaps this floppy has already been worn down? \n\n\n### 1: Felt Pad: Punched from self stick felt pad\n\n| | |\n|-----|-----|\n|Origin| unknown (gift from deramp5113) |\n| Material | Synthetic (melts instead of burning) |\n| Filament length | Longer than original | \n| Density | Loosely packed compared to original, but that may be because the original has been used for decades. |\n| Height | About twice the height of the original felt pad. |\n| Notes| This pad had fragments of dried glue which was removed under a microscope before testing. | \n\n#### Trial 1-A\n\n| | |\n|-|-|\n| Test duration | \u003e24 hours |\n| Testing method | Apple II attempting to boot a fresh disk |\n| Track # (of 40) | 0 (outermost) |\n| Test summary | **Fail** |\n\nResults: Track 0 has a black ring on the side facing the felt. That ring has data as the other side of the disk was formatted before the test, but it does not appear to have been affected at all. \n\n#### Trial 1-B\n\nThis is the same felt pad as in Trial 1-A. \n\n| | |\n|-|-|\n| Test duration | \u003e24 hours |\n| Testing method | [TRIBOLOGY.bas](TRIBOLOGY.bas) |\n| Track # (of 40) | 22 |\n| Test summary | **Pass** ??? |\n\nThere do appear to be light etch marks visible only when held to the light, but they are on side A, which is touching the head, not the felt. These did not occur in Trial 1-A. Could the felt be pushing too hard since it is too tall? Could it be a density issue? Or is it a problem with this drive's head? \n\n#### Trial 1-C\n\n\n| | |\n|-|-|\n| Test duration | 12 hours |\n| Material, height, etc. | This is the same felt pad as in Trial 1-B, but after being removed, examined under a microscope, and had the top layer and excess filaments trimmed off, making it similar in size to the original felt pad. The disk was the same from Trial 1-B since no marks had been left on the felt side. The drive head was also examined and cleaned.  \n| Testing method | [TRIBOLOGY.bas](TRIBOLOGY.bas) |\n| Track # (of 40) | 17 |\n| Test summary | **Pass** ? |\n\nNo marks on felt side. No apparent new marks on head side.\n\n### 2: Second Felt Pad: Punched from self stick felt pad\n\n| | |\n|-----|-----|\n|Origin| unknown (gift from deramp5113) |\n| Material | Synthetic (melts instead of burning) |\n| Filament length | Longer than original | \n| Density | Loosely packed compared to original, but that may be because the original has been used for decades. |\n| Notes| This new pad is from a second batch sent to me by deramp; the glue on it was not dried out. The same drive mechanism was used as in the other tests; only the felt pad and its plastic holder were replaced.| \n\n#### Trial 2-A\n\n| | |\n|-|-|\n| Test duration | 12 hours |\n| Testing method | [TRIBOLOGY.bas](TRIBOLOGY.bas) |\n| Track # (of 40) | 30 |\n| Test summary | **Fail** |\n\nResults: Track 30 has a faint, light ring on the side facing the felt. On the reverse (head) side, there is a prominent groove at track 30 which appears dark or light depending upon the angle of the light. \n\n### 3: Old (original?) felt pad in a Drive II\n\n| | |\n|-----|-----|\n|Origin| Likely originally shipped with the Apple Drive II |\n| Material | Synthetic (melts instead of burning) |\n| Filament length | Short | \n| Density | Firmly packed, coloration is yellowish brown, probably from age. |\n| Notes| This uses the same drive mechanism as the previous tests, but with a felt pad taken from a different drive. Unlike test 0, the floppy tested had never been used before.| \n\n#### Trial 3-A\n\n| | |\n|-|-|\n| Test duration | \u003e72 hours |\n| Testing method | [TRIBOLOGY.bas](TRIBOLOGY.bas) |\n| Track # (of 40) | 22 |\n| Test summary | **Pass** |\n\nResults: No marks whatsoever. This is a very strong indication that it is indeed the replacement felt pad that is causing the marks in tests 1 \u0026 2 despite them being most prominent on the head side of the disk.\n","project_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fhackerb9%2Ftribology","html_url":"https://awesome.ecosyste.ms/projects/github.com%2Fhackerb9%2Ftribology","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fhackerb9%2Ftribology/lists"}