Operating Systems: Three Easy Pieces

Flaws Found and Fixed

Here is a list of problems found and fixed in the book. Thanks so much to all of you for your help! Particular thanks to Kevin Liu, Ahmed Fikri, Srinivasan Thirunarayanan, Abhirami Senthilkumaran, Huanchen Zhang, Sivaraman Sivaraman, Finn Kuusisto, James Perry, and Rohan Das, the current leaders in fixes, suggestions, and other advice.

04/05/15 (Sandeep Ummadi): typo in threads-locks-usage
03/25/15 (Teri Zhao): bug in homework vsfs.py when out of inodes
03/17/15 (AmirBehzad Eslami): typos and suggestions in mystery-chapter
03/12/15 (Jakob Olandt): typo in threads-bugs
03/09/15 (Glen Granzow @ College of Idaho): typos in vm-beyondphys-policy and vm-beyondphys
03/09/15 (Perry Kivolowitz): bug in file-device
03/04/15 (Dheeraj Shetty @ NC State): awkward phrasing in vm-smalltables
03/04/15 (Jingxin Li): bug in table in threads-intro
03/03/15 (Angela Demke Brown @ Toronto): bug in vm-paging homework script
03/02/15 (Glen Granzow @ College of Idaho): typo in vm-freespace homeowork
02/25/15 (Glen Granzow @ College of Idaho): typos and fixes in vm-paging and vm-tlbs
02/25/15 (Perry Kivolowitz): a few small things in threads-locks
02/25/15 (Perry Kivolowitz): variable naming in threads-api
02/23/15 (Perry Kivolowitz): wording change and extra commentary on interrupt masking in threads-locks
02/20/15 (Michael Walfish @ NYU): added discussion on partial orderings in threads-bugs
02/19/15 (Michael Walfish @ NYU): typographical fix and bug in threads-bugs
02/17/15 (Glen Granzow @ College of Idaho): typo in cpu-sched homework, and bug in priority boost graph in cpu-sched-mlfq
02/17/15 (Michael Walfish @ NYU): fixes in threads-cv and threads-locks-usage as well as the suggestion to renumber tables and figures in a consistent way (a change that will happen slowly to all chapters with tables).
02/16/15 (Perry Kivolowitz): suggested clarification in vm-beyondphys-policy
02/13/15 (Glen Granzow @ College of Idaho): typo in cpu-mechanisms
02/09/15 (Perry Kivolowitz): some clarity suggested and hopefully provided in vm-paging
02/06/15 (Joe Jean @ NYU): clarifications around homework in cpu-intro
01/02/15 (Perry Kivolowitz): strong philosophical disagreement in vm-api which we eventually agreed with
01/31/15 (Michael Walfish @ NYU): typo in cpu-api
01/30/15 (David Hartman): typo in cpu-intro
01/28/15 (Dheeraj Shetty @ NC State): typo in vm-paging
01/26/15 (Emad Sadeghi): typo in intro
01/21/15 (Ali Razeen @ Duke): typo in vm-beyondphys-policy
01/11/15 (Huseyin Sular): typo in intro
01/11/15 (Brian Gorman): clarification in threads-api
01/03/15 (Authors): typos in file-integrity, file-raid, file-journaling, vm-paging, vm-tlbs
01/03/15 (Hao Chen): typo in file-raid
12/30/14 (Adriana Iamnitchi and class @ USF): typos and other fixes in cpu-mechanisms, vm-freespace, threads-sema, file-implement, file-ffs
12/30/14 (Hao Chen): typo in file-raid
12/29/14 (Erik Turk): typo in vm-vax
12/17/14 (Riccardo Mutschlechner): typos in file-lfs
12/17/14 (William Royle @ Grinnell): clarified number of I/Os in simple write in file-implement
12/14/14 (Yudong Sun): missing cite in dist-intro
12/10/14 (Hao Chen): typo in vm-paging figure 18.7
12/08/14 (Rohan Das @ Toronto): typos in vm-mechanism, vm-segmentation, vm-paging, vm-tlbs, threads-intro, threads-sema, file-intro
12/02/14 (John Brady @ Grinnell): type in file-lfs
11/24/14 (Itai Hass @ Toronto): typo in file-implement
11/24/14 (Jerod Weinman @ Grinnell): typo in file-implement
11/17/14 (Nick Weinandt): typo in file-journaling
11/11/14 (Yudong Sun): typo in threads-sema
11/06/14 (Itai Hass @ Toronto): typo in vm-mechanism
10/29/14 (Andrew Valencik @ Saint Mary's): typos in threads-intro homework
10/27/14 (Eduardo Stelmaszczyk): bug in threads-bugs
10/16/14 (Rohan Das @ Toronto): typo in cpu-sched
10/13/14 (Jerod Weinman @ Grinnell): clearer prose in threads-bugs
10/13/14 (Joel Kuntz @ Saint Mary's): typo in vm-paging
09/15/14 (Robert Ordonez): typo in vm-vax
10/04/14 (Jerod Weinman @ Grinnell): better fig placement in threads-locks
09/15/14 (Robert Ordonez): typo in vm-smalltables
09/23/14 (Aditya Venkataraman): typo in threads-api
09/17/14 (Jiao Dong @ Rutgers): correct attribution of Confucius quote.
09/15/14 (Robert Ordonez and class @ Southern Adventist): suggestions for improvement for cpu-sched
09/12/14 (Liang Yin): typo in vm-segmentation
09/08/14 (Caleb Sumner @ Southern Adventist U.): typo in cpu-api homework
09/03/14 (Rohan Pasalkar @ Minnesota): typos in file-lfs , file-integrity , dist-nfs
08/26/14 (Riccardo Mutschlechner): typos in file-implement
08/05/14 (Riccardo Mutschlechner): typos in file-intro, file-devices, file-disks, file-raid
08/01/14 (Riccardo Mutschlechner): typo in threads-cv
07/28/14 (Christoph Jaeger @ HTWK Leipzig): bug in diagram in vm-mechanism
07/02/14 (Jan Reineke @ Saarland): graph bug in cpu-sched-mlfq
07/02/14 (Kartik Singhal): typo in cpu-intro citations
06/30/14 (Hugo Diaz): typo in intro code snippet
06/10/14 (Adam Drescher @ WUSTL): many suggestions and fixed in vm-paging, vm-segmentation, vm-tlbs, cpu-mechanisms, cpu-intro, cpu-sched-lottery, file-ffs, vm-smalltables, vm-intro, vm-freespace, vm-mechanism, cpu-sched-multi, cpu-sched-mlfq
06/08/14 (Akiel Khan): typo in threads-intro
05/29/14 (Riccardo Mutschlechner): typo in vm-paging
05/22/14 (Neeraj Badlani @ NC State): table typos in threads-cv
05/22/14 (Mohammed Alali @ Delaware): typo in vm-freespace
05/19/14 (Adam Drescher @ WUSTL): typo in cpu-sched
05/18/14 (Mohammed Alali @ Delaware): typo in vm-intro
05/18/14 (Adam Drescher @ WUSTL): typo in cpu-sched
05/15/14 (Chien-Chung Shen @ Delaware): typo in file-implement
05/13/14 (Chien-Chung Shen @ Delaware): typo in file-intro
05/03/14 (Samer Al-Kiswany): corrections in file-intro , file-implementation , file-journaling , file-lfs , file-integrity
05/02/14 (Dorian Arnold @ New Mexico): bug in disk.py homework tool
05/01/14 (Chien-Chung Shen @ Delaware): consistency problem in vm-tlbs
04/29/14 (Satish Chebrolu @ NetApp): typo in cpu-mechanism
04/28/14 (Chien-Chung Shen @ Delaware): consistency problem in vm-freespace
04/25/14 (Chien-Chung Shen @ Delaware): typo in vm-paging
04/16/14 (Leslie Schultz): typo in file-devices
04/13/14 (Patricio Jara): bug in Zemaphore code in threads-sema
04/07/14 (Mohammed Alali @ Delaware): typo in threads-locks
03/31/14 (Chien-Chung Shen @ Delaware): bad cite in vm-api
03/22/14 (Chien-Chung Shen @ Delaware): two sema value mistakes in threads-sema
03/14/14 (Shreevatsa R.): typos in intro and vm-smalltables
03/12/14 (Jonathan Perry @ MIT): figure incorrect in file-disk
02/28/14 (Brian Kroth): typo in vm-beyondphys-policy
02/23/14 (Ming Chen @ Stonybrook): missing cite in file-journaling
02/06/14 (Jun He): typos in file-intro and vm-mechanism
01/20/14 (Bjorn Lindberg): clarified random number generation in cpu-sched-lottery
01/19/14 (Thomas Griebel): added cover art
01/19/14 (Matty Williams): suggestion for hyperlinks, etc. in e-version
01/19/14 (Nelson Gomez): typo in intro
01/19/14 (Bobby Jack): typos in intro
01/18/14 (Varun Vats): typo in preface
01/06/14 (Biswajit Mazumder @ Clemson): Clarification in vm-segmentation
01/06/14 (Nghia Huynh @ Texas): Incorrect type in lowlevellock in threads-locks
12/20/13 (Ernst Biersack @ France): typo in file-raid homework
12/17/13 (Emmett Witchel @ Texas): incorrect bit about NFS permissions dist-nfs
12/05/13 (Satyanarayana Shanmugam): typo in file-lfs picture
12/03/13 (Ruslan Kiselev): small fixes in file-disk and file-raid
11/22/13 (Satyanarayana Shanmugam): typos in file-integrity
11/14/13 (Satyanarayana Shanmugam): typo in RAID homework file-raid
10/18/13 (Huanchen Zhang): typo in dist-nfs
10/14/13 (Satyanarayana Shanmugam): clarified OOM in vm-beyondphys-policy
10/11/13 (Masashi Kishikawa): fixed two bugs in threads-sema
10/11/13 (Satyanarayana Shanmugam): small bug in threads-cv
09/20/13 (Masashi Kishikawa): fixed bug in figure in vm-freespace
09/17/13 (Tongxin Zheng): wrong modes in cpu-mechanism
08/19/13 (Anand Mundada): small typo in threads-sema
08/12/13 (Torin Rudeen @ Princeton): many fixed in threads-locks-usage
08/03/13 (Charlotte Kissinger): typos in file-devices and dialogue-persistence and file-raid
07/31/13 (Deepika Muthukumar): wrong XOR calculation in file-integrity
07/26/13 (Yue Zhuo): missing shift in vm-smalltables ; also encouragement to update the darn website, leading to a slew of updates
03/15/13 (Hrishikesh Amur): overclaim about windows device drivers
03/14/13 (Yufui Ren): graph typo in cpu-sched
02/26/13 (Ajaykrishna Raghavan): typo in cites in vm-freespace
02/21/13 (Nathan Dipiazza): typo in vm-beyondphys
02/17/13 (Zuyu Zhang): typo in cpu-mechanism
01/24/13 (Kaushik Kannan): footnote about AS randomization needed
01/21/13 (Lei Tian @ Nebraska-Lincoln): bug in disk.py homework tool
01/21/13 (Varun Vats): typo in threads-intro
12/19/12 (B. Brahmananda Reddy): typo in cpu-mechanism
12/01/12 (Sandeep Ummadi): bugs in vmm-intro , dialogue-concurrency
10/20/12 (Joel Sommers @ Colgate): -pthread not -lpthread on link line in intro, threads-api, threads-intro
10/18/12 (Xu Di): permissions detail in file-implementation , bug in disk simulator
10/14/12 (Joel Sommers @ Colgate): missing destroy calls in threads-api
10/01/12 (Jerod Weinman @ Grinnell): typos in vm-freespace , file-disks , file-journaling
09/01/12 (David Hanle): typo in vm-segmentation
08/20/12 (Bala Subrahmanyam Kambala): typo in dialogue-virtualization
06/20/12 (Benita Bose): typos in file-ffs, dist-intro, file-journaling, file-implementation
05/19/12 (Suriyhaprakhas Balaram Sankari): typos in file-devices , file-disks
05/17/12 (Sharad Punuganti): typos in dist-nfs , file-intro , threads-intro , dist-intro
05/14/12 (Adam Eggum): disk simulator crash
05/12/12 (Guilherme Baptista): typos in threads-sema
04/24/12 (Finn Kuusisto): Many typos in cpu-api , cpu-mechanism , cpu-sched , vm-segmentation , vm-freespace (actually used the word <“>suck<”> by accident!), vm-smalltables , vm-beyondphys-policy , threads-cv , file-journaling
04/24/12 (Sivaraman Sivaraman): mistake in math term in file-disks
04/12/12 (James Perry @ UM-D): many typos in file-journaling, file-implementation, file-ffs
04/03/12 (Jake Gillberg): wrong variable in threads-cv
03/22/12 (Emily Jacobson): RAID terminology fix in file-raid
03/12/12 (Sivaraman Sivaraman): two typos in threads-api and one small but critical fix in vm-segmentation example calculation.
03/12/12 (Benita Bose): typo in vm-dialogue , and a few problems in threads-intro
03/10/12 (Sivaraman Sivaraman): cache sizes of N, N+1 mixed up in vm-beyondphys-policy
03/05/12 (Sivaraman Sivaraman): typo in vm-mechanism , which I kept claiming wasn't there! (but it was)
03/05/12 (Shreevatsa R.): many fixes in threads-lock , threads-cv
03/05/12 (Tony Adkins): typo in dialogue-concurrency
03/01/12 (Benita Bose): typo in vm-mechanism
03/01/12 (Shreevatsa R.): typos in threads-init and threads-api
02/14/12 (James Perry @ UM-D): typo in cpu-sched-lottery ; typo in cpu-api, vm-tlbs, vm-intro, threads-api, file-implementation
02/14/12 (Ripudaman Singh): small code bug in threads-deadlock
02/11/12 (Charlotte Kissinger): Figures in cpu-sched are incorrectly labeled
02/09/12 (Tony Adkins): Code example in vm-tlbs is unclear
02/04/12 (Xiang Peng): unrestricted in vm-mechanism should be restricted (or privileged)
Fall'12 (Srinivasan Thirunarayanan): Fixes to file-implementation, file-journaling, file-lfs, dist-afs, file-devices, threads-sema, vm-intro, file-implementation homework, file-disks, vm-beyondphys-policy, vm-beyondphys, vm-smalltables, vm-paging, vm-paging homework, vm-relocation, cpu-api
Fall'12 (Abhirami Senthilkumaran): Fixes to file-intro, file-implementation, file-journaling, file-lfs, file-disk, vmm-intro, vm-beyondphys-policy, cpu-sched-lottery, intro, vm-smalltables
Fall'12 (Huanchen Zhang): Fixes to file-raid, file-implementation, file-journaling, vm-mechanism, vm-tlbs, vm-smalltables, threads-locks, cpu-sched
Fall'12 (Henry Abbey): Fixes to threads-deadlock, file-devices, file-implementation, dist-nfs, vm-tlbs
Fall'12 (Sy Jin Cheah): Fixes to intro, file implementation, file-ffs, file-lfs, dist-afs, threads-cv
Fall'12 (Cara Lauritzen): Fixes to threads-deadlock, file-devices
Fall'12 (Brennan Payne): Suggestion for more/better summaries, fixes to vm-segmentation
Fall'12 (Ripudaman Singh): Fixes to vm-paging, vm-beyondphys-policy , homeworks for both
Fall'12 (Nathan Sullivan): Fixes to intro, cpu-sched-lottery, vm-paging, vm-beyondphys, vm-beyondphys-policy, lab-tutorial
Fall'12 (Lihao Wang): Fixes to vm-tlbs, vm-relocation
Fall'12 (Balasubramanian): Fixes to cpu-api, cpu-mechanisms
Fall'12 (Meng Huang): Fixes to file-implementation, threads-cv
Fall'12 (Ross Aiken): Files to file-journaling
Fall'12 (Seth Pollen): Fixes to file-journaling
09/20/11 (Huanchen Zhang): Process intro: extra will
09/20/11 (Srinivasan Thirunarayanan): Process API: typo in code snippet.
09/20/11 (Brennan Payne): Segmentation: typo in we get a physical address of 39016, which is not get the correct physical address.
09/06/11 (Martha Ferris): Intro: to difficult s.b. to be difficult ... Intro: not to have write in assembly s.b. not to have to write in assembly
07/30/11 (Karl Wallinger): Scheduling: ...of course there a number of different... missing an are
06/14/11 (Karl Wallinger): Intro: extra would
06/08/11 (Mike Griepentrog): Lab: Expert C Programming is still in print
05/20/11 (Ahmed Fikri): About 30 different comments, too many to list here
05/14/11 (Dustin Metzler): Chapter numbering confusing
05/11/11 (Radford Smith): FFS: to allocate the data blocks of an file ... LFS: and hence to overall name of the log-structured file system ... LFS: (where NxM) .. LFS: On top the mechanism described above
05/10/11 (Dustin Passofaro): AFS: state file should be stale file ... NFS if case should be in case ... RAID: other interesting that should be other interesting ideas that ... Intro: it simple -> it simply ... Deadlock: more more should be more ... Locks: it simple calls s.b. it simply calls ... Devices: for the OS send s.b. for the OS to send
05/10/11 (Alex Wyler): file-journaling now and not not in we are not/now also writing to the journal first
05/06/11 (Kevin Liu): cpu-api complete mispelled as comlplete
04/27/11 (Radford Smith): threads-locks-hw forgot lock_t at end of typedef.
04/25/11 (Murugan Kandaswamy): dist-nfs ... server (not client ) does not reply in a timely manner?
03/11/11 (Ryland Herrick): threads-sema Lookups , not inserts .
03/11/11 (Ryland Herrick): threads-locks-hw Missing ! in LL/SC lock.
03/02/11 (Alex Wyler): paging-smalltables Bits PFN7 and PT7 don't exist.
03/02/11 (Jay Lim): vmm-intro discuss not discus .
03/02/11 (Zef RosnBrick): vm-segmentation fixed is not get the correct physical address by removing get
03/02/11 (Zef RosnBrick): cpu-sched-mlfq replaced of with than
02/23/11 (Dan Soendergaard @ U. Aarhus): dialogue-virtualization illusion misspelled as illision
05/10/10 (Tuo Wang): vm-relocation 32KB is 32768
05/10/10 (Tuo Wang): vm-relocation fetch from correct addresses
05/10/10 (Tuo Wang): vm-paging number of numerical typos
05/10/10 (Tuo Wang): vm-smalltables 55 not 45
05/10/10 (Tuo Wang): file-lfs unclear sentence about buffering
05/08/10 (Matt Reichoff): file-raid design should be designed
03/05/10 (Cody Hanson): vm-relocation you can how should be you can see how
01/24/10 (Natasha Eilbert): lab-tutorial p.1 you said Unlike Java, there is no connection between the file name and the contents of the file; because of that, just use your common sense in naming files. After thinking about this for a little bit I got what you meant, but at first was confused and thought you were saying that in C there actually _shouldn't_ be any relation at all between the filename and its contents! Maybe you could say something like no enforced connection .
01/24/10 (Natasha Eilbert): lab-tutorial p. 4 that that should just be that
01/24/10 (Natasha Eilbert): lab-tutorial p. 8 defintion should be definition
10/24/09 (Kevin Liu): m2 - Sample assembly code on page two shows address 128, 130 and 134. However, the addresses in the diagram on page 3 shows addresses 128, 130, 133.
10/24/09 (Kevin Liu): m3 page 5: next 11 bits should be next 12 bits
10/24/09 (Kevin Liu): m3 page 5: In the C pseucode-code section, && should be replaced by &.
10/24/09 (Kevin Liu): m3 page 8: Perhaps mention that the free list management policy does not get rid of external fragmentation, but simply tries to minimize it.
10/24/09 (Kevin Liu): m4 page 4: The example showing the translation from virtual address 21 seems to have a mistake. We picked PFN 5, however, going by Figure 12.2, we should have picked PFN 7. This would mean that our physical address should be 117 instead of 85.
10/24/09 (Kevin Liu): m5 page 2: CISC is defined as complex-instruction set computing , however, RISC is defined as reduced-instruction set computers . Should change one of the two to make the definitions consistent.
10/24/09 (Kevin Liu): m6 page 3: Specifically, we use a tiny 16KB address space with 1KB pages (Figure 14.2) . Should be Figure 14.1.
10/24/09 (Kevin Liu): m6 page 8: At PhysAddr1 (some physical address, or, if the page directory is page-aligned, just the physical frame number), we have the first chunk of 16 page table entries for the first 16 VPNs in the address space. It would look something like what you see in Figure 14.2. Should be Figure 14.3. Also, the text refers to the diagrams as Figures but they are actually labeled as Tables .
10/24/09 (Kevin Liu): m6 page 10: page 254 of VA space is mapped to PFN 55, not 45.
10/24/09 (Kevin Liu): m8 page 10: However, in many cases the importance of said algorithms has decreased, as the discrepancy between memory-access and disk-access times has increased. Should be decreased, not increased.