Web Resources for CS3650 (Computer Systems)

And there is now a: study guide for the final exam
and the: older study guide for the midterm

NOTE:
The office hours are as stated on the syllabus (Tues. and Fri., 5:15 - 6:30; 336 WVH or nearby, for Spring, 2025), and by appointment. I am typically still in my office at least until 7pm.

NOTE:
And further office hours: TA: Punith Subashchandra Please find the Zoom invitation attached for the office hours. Let me know if you have any concerns or if any adjustments are needed.
[ The Zoom link was mailed to the class. Please ask a classmate or me, if you didn't note down the Zoom link. ]

NOTE: Extra TA office hours (in addition to 5:30 - 6:30, Tues./Fri. by Prof. Cooperman, as noted above):
Regular Office Hours: Monday and Friday, 12-1 PM EST
TA: Manasa Rao
Mode: Online
Every week on Mon, Fri,
Join Zoom Meeting
[ The Zoom link was mailed to the class. Please ask a classmate or me, if you didn't note down the Zoom link. ]

Course basics: Here are some immediate resources in the course for doing homework, following the readings, etc.

Course home:

The course materials will always be available either from this web page or from the course directory on the Khoury Linux computers: /course/cs3650/.

Syllabus:

The syllabus contains the required readings in the textbook. It's available from the link or from /course/cs3650/ (the course directory) on Khoury Linux computers. Note especially our online textbook ostep.org.

Homework:

The homework subdirectory of the course directory contains all course homework, and the course directory contains all handouts.

Help directory:

The course directory includes a help directory. There are two older reviews of UNIX there. But please consider this excellent modern introduction to UNIX by M. Stonebank. (or alt, with updates to Linux/bash by C. Tothill)

Linux:

The course is based on Linux (the third of the three popular operating systems). If you do not yet have a Khoury Linux account, get one. If you are not fluent in the basics of Linux/UNIX, please go to any of the good tutorials on the Web. Personally, I like: *** this Linux tutorial *** (from M. Stonebank, U. of Surrey, England), or this *** updated one for Linux/bash *** (by C. Tothill)
Other useful tips on Linux:

1. Productivity tip: In most settings: the four cursor keys work (for editing the current or previous commands); and the <TAB> key works (for auto-completion of filenames and commands).
2. If you're using Apple (the second most popular operating system), the terminal window provides you with a UNIX-like environment. It may differ from true Linux in small ways. You may need to install extra packages for Mac OS. You should still test your homework solution on the Khoury login commputer, since that will be the standard for correctness.
3. If you're using Windows (the most popular operating system), you can install WSL (Windows Subsytem for Linux). Then go to the Microsoft Store, and install a Linux. If you are unsure of which Linux distribution to use, Ubuntu is a common first choice for those unfamiliar with Linux, especially an Ubuntu labelled "LTS" (Long Term Support". This gives you a Linux virtual machine side-by-side with Windows. Some "gotchas" and workarounds follow.
   If installing Ubuntu from the Microsoft Store and it fails with an error code, try executing wsl --update in PowerShell with admin privlege.
   After installing WSL, a known, older bug from May, 2021 causes the vmmem process to consume a lot of CPU time at wake-after-sleep, if WSL was running. There is a workaround here.
   Some people may also need to turn on virtualization in their BIOS. After entering BIOS, examine all options in all tabs with the letter 'v'. For me, the option was "AMD SVM".)
4. In order to copy files between Windows and WSL, I create a link inside WSL to the 'Downloads' folder:
cd
ls /mnt/c/Users
# For me, I am user genec in Windows. So, I then type:
ln -s /mnt/c/Users/genec/Downloads ./
# You can now copy (cp) between ~/Downloads and ~ in WSL,
# where '~' is the Linux shortcut for your home directory.
5. Similarly, you can copy between Windows Desktop and WSL. In my case, I type:
cd
ln -s /mnt/c/Users/genec/Desktop ./
# OR:
ln -s /mnt/c/Users/genec/OneDrive/Desktop ./
# Try both forms. It depends on where Windows put your Desktop.
6. Whether you use Windows/WSL or Apple Terminal, you'll need 'ssh' and 'scp':
# Logging into Khoury login: (You'll need this to submit.)
ssh USER@login.ccs.neu.edu # Replace 'USER' by your Khoury username
# Copying your local laptop files to Khoury login: (You'll need this to submit.)
# Note the ':' at the end. You can add a Khoury directory in your account.
# Or, you can leave it blank after ':', and the file is copied to your home dir.
scp myhw.tar.gz USER@login.ccs.neu.edu: # Note: After ':' Default dir is home dir
For help, try: man ssh and man scp.
   
7. And note one gotcha. If you use the wrong password three times with 'ssh', then Khoury login (as of 2025) logs your IP address, and locks you out for 3 days.
   WORKAROUND: Set up a hotspot with your smartphone, and connect your laptop to the hotspot. The smartphone will have a different IP address.
8. But if you insist on using Windows, but not WSL, then please try putty (substitute for 'ssh') and WinSCP (substitute for 'scp'). For 'ssh' without WSL, you can alternatively install OpenSSH for Windows.

Linux editors:

Please also note the directory for UNIX (Linux) editors. On Khoury Linux, try: cd /course/cs3650/unix-editors. The editor vi is a popular choice. To learn vi (estimated time: one hour), login to Khoury Linux and do:
    vi /course/cs3650/editors-unix/vitutor.vi
and follow the on-screen instructions.

Common Linux Commands:

Here is one web site (Common Linux Commands) with about 30 common Linux commands. If you haven't used Linux much, try a quick review of these commands (passive knowledge only). If you need more, there are plenty of great text and video tutorials on the Linux command line.

RISC-V assembly language:

The assembly portion of the course will be based on RISC-V. Please download the RARS Simulator for RISC-V (inspired by MARS for MIPS assembly), for use with RISC-V assembly.

1. Quick Reference: "RISC-V quick reference" online (or alt, but missing pseudo instructions; or alt) (all inspired by MIPS "green card")
2. Assembly "cheat sheet": RISC-V "cheat sheet" (and for each instruction, click on the "Project F guide" at the right for a fuller description of that category of instructions)
3. Home page for RARS simulator and documentation: RARS on github
4. System calls: "Environment calls"
5. Assembler directives: Assembler directives
6. Assembly manual: Assembly instructoins supported by RARS
7. Function calling convention: Conventions to make function calls (and system calls)

Google for RISC-V, and you'll find other RISC-V resources, but I find the above resources to be sufficient, and self-contained.

If you'd like examples of excerpts of RISC-V assembly, as translated from a C program, try the Godbolt Compiler Explorer (choose C language and "RISC-V (32-bits) gcc" from the menus in the two panes; and deselect "Compiler to binary object" in the "output" menu of the right-hand pane);
and see this post describing it: Project F: RISC-V Assembler: Compiler Explorer. In fact, the Compiler Explorer can generate the commonly used: RISC-V, MIPS, ARM, and x86-64 (Intel/AMD) assembly. And the Project F post even has more examples of paradigms for RISC-V, in case you didn't like the ones above.

And the Compiler Explorer can generate the assembly using the gcc compiler or the clang compiler.

C language:

We will assume knowledge of the C  language (the core of Java, but including primitive types, only). For a more extensive overview of C, consider a good, free on-line C book by Mike Banahan, Declan Brady and Mark Doran. Since Java does not have pointers, we will study C pointers in class.

GDB debugger, gcc compiler, etc.:

As you use Linux, please especially practice using GDB (GNU debugger). This will help when you test your homeworks under Linux. It will also reward you with more productive debugging for the rest of your computer science career. (Here are some local help files for Linux and its compilers, editors, etc., but please consult GDB closer to the bottom of this page, or else the rich set of help pages now on the Web.)

Python

See materials on Python, and the Python subdirectory

UNIX xv6

The original UNIX was small enough that one can read all of the code, with the right guidance. The UNIX xv6 subdirectory has an easy-to-read hyperlinked version of UNIX xv6, with about 7,000 lines of code (about 100 pages of code).

Thread synchronization

"thread-synch" subdirectory (notes on basic use of mutex, semaphore and condition variables)

Undergraduate tutoring (but no longer available):

Khoury College used to offer free undergraduate upper-class tutoriing as of 2020. It seems to be gone in recent years, but let me know if such a resource again appears.

Going beyond (enrichment material):

• Some students have asked about a book for a more advanced introduction to Linux and systems programming. This book goes well beyond what is needed for the course. But for those who are interested, there is:
       Advanced UNIX Programming, by Marc J. Rochkind (free online access through library.northeastern.edu)
• If you're interested in reading the original UNIX research paper, which announced the implementation of UNIX to the world, see The UNIX Time-Sharing System (1974). (or here

Text supplements (optional) for course:

• Online text: ostep.org (The final will cover all of the chapters on concurrency; and also the chapters on files from "Files and Directories" through "Fast File System (FFS)": superblock, inode, etc. --- you do not need to read about I/O Devices, disk drives and disk arrays.)
• xv6-rev8.pdf:
  UNIX xv6 (hyperlinked):
  OR MAYBE: UNIX xv6 (hyperlinked): (systems team re-organizing our web directories?)
  xv6 source code for UNIX kernel: especially see:
  proc.c,h (process table);
  swtch.S (context switch to a new process);
  spinlock.c,h (spinlock, like a mutex);
  file.c,h (file descriptor pointing to an open file);
  fs.c,h (filesystem using superblock, inode, etc.);
  pipe.c,h (pipes: e.g., ls | wc );
  bio.c,h (buffered I/O: linked list of buffers acting as a cache for disk blocks or disk sectors).
  If you are curious, you can also read about the history of xv6.
• Book with commentary on xv6-rev8 (UNIX kernel)
• Python (based on materials in /course/cs3650/python)
• Early history of Python (just for fun)
• Machine Learning for Beginners: An Introduction to Neural Networks (After multi-threading, one could study GPUs (massive SIMD threads). The "killer app" for GPUs is Neural Networks. GPUs allow more layers in the network, often called "deep learning". More recently, we have seen Generative AI (e.g., LLMs, ChatGPT, etc.) based on a transformer architecture, which is based on neural networks.)
  

RISC-V Simulator (RARS) for Assembly Language homework:

In Spring, 2025, we are now switching from MIPS to RISC-V CPUs. These old MIPS resources for MARS/MIPS may provide useful hints for when you use the RARS/RISC-V simulator. This is because RARS was inspired by MARS. But this section will eventually mostly be deleted, with minor parts updated for RARS.

1. The software is distributed as a Java .jar file. It requires Java 8 or later. Here are installation instructions for Windows, and installation instructions for Mac, and manual install for all three operating systems.
2. Then download RARS. Here is the RARS documentation. This leads you to the Downloads page (currently v1.6), and at the bottom of that page, there is a rars1_6.jar link. Click on the jar link, and you should now have RARS working.
3. To begin running the simulator, go inside the folder, and double-click on the Mars.jar icon. Alternatively, if running from the command line in Linux, type: java -jar jars1_6.jar
4. Here are some youtube RARS tutorials by XDoesTech (with transcripts): Part 1, Part 2, Part 3 (including syscalls), Part 3.1, Part 4.1: Memory, Endianness,. See his github page for reference information files and code files that he uses.
5. Notice that the RARS documentation also has an examples folder, with some example RISC-V programs that you can run. However, most of those files are missing a "main" routine.
6. And here is an old video of running the old MARS simulator. That will show MIPS assembly, instead of RISC-V assembly. But the video is still useful for showing the user interface of RARS: Online video demo of the Mars simulator.
7. OLDER MARS; YOU NEED RARS: There is a MIPS Assembly language simulator with free downloads available (and local copy) and online documentation.
8. GOTCHAS: There are several important things to watch out for in RARS.
   1. When you use the menu "File -> Open", you may wish to select "Files of Type:" in the dialog box, and then choose "Assembler Files (*.asm; *.s)", instead of "All Files".
   2. The "Messages" pane at the bottom also keeps text from older runs. Click the "Clear" button before doing a new run.
   3. When you hit the "Assemble" menu item, any error messages about failure to assemble are in the bottom window pane, tab: "Messages". Input/Output from your program is in the bottom window pane, tab: "Run I/O"
   4. If you paste assembly code into the edit window pane, you should save that code to a file before you assemble it, or you may lose it.
   5. In the "Execute" tab, note that there is a column, "Source", showing the line number that this came from in the "Edit" tab.
   6. In the "Execute" tab, you can set a breakpoint by checking the "Bkpt" column. This is similar to the Eclipse GUI, or the GDB "break" command. You can then press the "Continue" icon (green triangle at top), or the menu "Run -> Go", which is equivalent to the GDB "continue" command.
   7. If you have selected a box with your mouse (e.g. "Value" box in the data window pane, or "Register" box), then you can modify that value, before continuing to single-step in RARS. (This is similar to "(gdb) set VARIABLE = VALUE".)
   8. If your program stops at an error, read the "Messages" at the bottom for the cause of the error, and then hit the "Backstep" menu item to see what caused that error. Continue hitting "Backstep" or "Singlestep" in order to identify the error. Set "Clear" to clear the previous messages in the "Messages" pane..
   9. Your main routine must call the "exit" system call to terminate. It may not simply call return ("jr ra"). For information on syscalls, click on the "Help" menu in RARS, and then click on syscalls. You'll see that "Exit" is syscall number 10.
9. One of the nicer features of this software is a limited backstep capability (opposite of single-step) for debugging. In addition, the help menu includes a short summary of the MIPS assembly instructions. In general, I like this IDE for assembly even better than some of the IDEs that I have seen for C/C++/Java. (The one feature that I found a little unintuitive is that if you want to look at the stack (for example) instead of data, you must go to the Data Segment window pane, and use the drop-down menu at the bottom of that pane to choose "current sp" instead of ".data".)
10. You can also run RARS from the command line:
    cd ~/Downloads # In WSL, assuming you have a Downloads link
cd C:\Users\genec\Downloads # In Windows Terminal application
java -jar ./rars1_6.jar ./factorial.asm
11. I'd appreciate if if you could be on the lookout for any unusual issues, and report them promptly (along with possible workarounds), so the rest of the class can benefit. Thanks very much for your help on this.

The GNU debugger

GDB (GNU DeBugger):
  A Few Simple Debugging Commands Save You Hours of Work

        INVOKING gdb:
          gdb --args  
          Example:  gdb --args ./a.out myargs

        COMMON gdb COMMANDS:
          BREAKPOINTS:  break, continue
          STARTING:  break main, run
          WHERE AM I:  info threads, thread 1; where, frame 2; list
          PRINT:  ptype, print  (   ptype argv[0]; print argv[0]   )
          EXECUTING:  next, step, until, finish, continue
            (next line, step inside fnc, until previously
             unseen line (escape a loop), finish current fnc,
             continue to next breakpoint)
          EXIT:  quit
          < Cursor keys work, TAB provides auto-complete >
          PARENT AND CHILD PROCESSES:
            set follow-fork-mode child
              (after call to fork(), switch to debugging child process)
          DEBUGGING INFINITE LOOP:
            run; TYPE ^C (ctrl-C) TO TALK TO gdb; where; print var1; etc.
          HELP:  help    e.g.: (gdb) help continue

        ADVANCED gdb: USING gdbinit:
          In a more sophisticated debugging session, you may have to try
          multiple GDB sessions.  To do this, you will want to try doing:
            gdb -x gdbinit --args ./a.out myargs
          First, create a gdbinit file. An easy way is, in your last GDB session,
            (gdb) show commands
          Then copy-paste those comamnds into gdbinit and edit as desired.
          Then at the top of gdbinit, insert:
            # gdb -x gdbinit --args ./a.out myargs  [Customize as needed]
            set breakpoint pending on
            set pagination off
            # Stop if about to exit:
            break _exit           
            # Continue w/ output of 'show commands'; Extend and modify as needed

        MORE ADVANCED gdb:
          info function 
            IF DEBUGGING C++ CODE, you will find this useful, in order
            to discover the full GDB name of your target method.
          macro expand MACRO_FNC(ARG)  [requires 'gdb -g3']
          debugging child after fork:
            set follow-fork-mode child
            break fork
            run
          EXTENDED "WHERE AM I":
            set detach-on-fork off
            info inferiors; inferior 2
            info threads; thread 1
              NOTE:  The qualified thread number is: .
                     So, 'thread 2.3' switches to thread 3 in inferior 2.
            where; frame 2
            list; print myvariable

  NOTE: For those who like a full-screen display of the current code, try the command ^Xa (ctrl-X a) to turn full-screen mode on and off. Also, try: (gdb) layout split
And finally, try "focus cmd" and "focus src", or ^Xo, to decide which pane you want your cursor keys to operate on.

  NOTE: For those who like to try a reversible version of GDB, see rr-project.org (for GDB with reverse execution)

  NOTE: For a _really cool_ GDB interface, look at: https://github.com/cyrus-and/gdb-dashboard. To try it out, just go to the .gdbinit file from that web site, and then copy the code into a local file, gdbinit-dashboard, and then execute source gdbinit-dashboard in GDB. Personally, I like to use Dashboard by displaying the whole dashboard in another terminal.

There are some good introductory materials for Python in the instructor's directory. After trying those out, here are some other Python background materials:

Python

• Dive Into Python (free Python book, well-written, but last updated in May, 2004)
• Python idioms for advanced programmers
• MIT beginning programming course (6.00), based on Python (MIT Open Courseware: full lectures, homework, etc.)

• NEWS (Apr., 25, 2025): TSMC to begin production of next-gen A14 (1.4nm) process in 2028 (1.4nm is about 6 silicon diameters)
• NEWS (Apr., 3, 2025): Semicon China 2025 - The Rise of SiCarrier
• NEWS (Mar., 25, 2025): TSMC to start 2nm orders in April, with iPhone 18 set to feature 2nm A20 chip (accepting production order of A20 for iPhone 18, and others, in April, 2025)
• NEWS (Jan., 3, 2025): TSMC completes risk production of 2nm process with 5,000 wafers (with mass productoin in second half of 2026; Apple and NVIDIA are the largest customers)
• NEWS (Dec., 16, 2024): Xpeng reportedly considering shelving plans to adopt Thor as Nvidia chip suffers delays
• NEWS (Mar., 27, 2024): TSMC sees strong demand for 3nm chips with orders from Apple, Intel, and AMD: report
• NEWS (Feb., 22, 2024): Intel to adopt high-NA EUV in 14A process manufacturing
• NEWS (Jan., 30, 2024): Intel's Nova Lake processor to adopt TSMC 2nm process technology
• NEWS (Oct., 12, 2023): RISC-V Wants All Your Cores (a surprising ambition for RISC-V to be used on GPUs, GPGPU computing, etc.; excellent!)
• NEWS (Jan., 29, 2024): Canon expects to ship nanoimprint lithography machines by 2024
  • A Deep Dive into Canon's Nanoimprint Lithography (youtube; excellent!)
• NEWS (Oct., 20, 2023): Samsung reveals eMRAM and BCD roadmap while pushing automotive chip down to 2 nm (and see Wikipedia article on how close MRAM is toward competing with other RAM technologies)
• NEWS (Sept., 19, 2023): TSMC to put off 2nm mass production until 2026
• NEWS (Sept., 17, 2023): Development of SSMB EUV Light Source at THU (Tsinghua University) (and see more recent Chinese blog; click on "Google Translate")
• NEWS (Jul., 30, 2023): Japan is eyeing heterogeneous integration on way to mass-produce 2nm chips
• NEWS (Jul., 3, 2023): Samsung set to commercialize 2nm chips in 2025, 1.4nm by 2027
• NEWS (Jun., 28, 2023): Surging iPhone 15 series orders may boost TSMC revenue in the third quarter by 11% (Mew chip moving to 3nm, and Apple will book 90% of TSMC's 3nm production.)
• NEWS (Apr., 23, 2023): TSMC starts 2nm pre-production, targets mass production by 2025: report
• NEWS (Apr., 23, 2023): Tech war: China's top memory chip maker YMTC making progress in producing advanced 3D NAND products with locally sourced equipment: sources (or here)
• NEWS (Dec., 30, 2022): TSMC gearing up for 3nm capacity expansion, 2nm fab construction
• NEWS (Dec., 5, 2022): Intel unveils 2D and 3D IC research breakthroughs to extend Moore's Law
• Moore's Law and future chip technologies:
  • Imec Presents Sub-1nm Process and Transistor Roadmap Until 2036: From Nanometers to the Angstrom Era (Future Summit event, Imec, May 21, 2022))
  • Intel Charts Course to Trillion-Transistor Chips: 2D Transistor Materials, 3D Packaging Research (IEDM 2022; Dec. 4, 2022)
    • Follow-up: "Celebrating 75 Years of the Transistor! A Look at the Evolution of Moore's Law Innovation"
• NEWS (Oct., 14, 2022): TSMC to see 3nm generate 4-6% of 2023 revenue
• NEWS (Oct., 7, 2022): Apple preparing for 2nm chips
• NEWS (Oct., 4, 2022): Samsung plans 1.4nm for 2027 while polishing up 3D packaging technology
• NEWS (Sept, 21, 2022): Nvidia launches next-gen GeForce RTX built on TSMC N4 node
• NEWS (July 19, 2022): Competition in 3nm smartphone AP market to take place in 2H23
• NEWS (July 12, 2022): Volkswagen constructing first in-house battery plant in Europe, considering 'big moves' in China
• NEWS (Apr. 21, 2022): US bid to boost chipmaking to be expensive and wasteful, says TSMC founder Morris Chang
• NEWS (Feb. 21, 2022): Global chipmakers find ways to improve competitiveness ($440B, $380B, and $280B capital expenditures in 2022 by TSMC, Samsung and Intel)
• NEWS (Jan. 19, 2022): Intel is on track to adopt 0.55 High-NA EUV lithography in 2025 ("NA" is "numerical aperture"; or alt or alt2)
• NEWS (Dec. 7, 2021): The Great Tech Rivalry: China vs the U.S. (by Avoiding Great Power War Project at Harvard University's Belfter Center; while an excellent review of technical progress in the U.S. and China, it unfortunately does not review the fast rising technical progress in India)
• NEWS (12/24/21): TSMC to move 3nm process to commercial production in 4Q22
• NEWS (12/23/21): Autonomous delivery picking up in US
• NEWS (12/1/21): TSMC enters pilot production of 3nm chips
• NEWS (10/8/21): TSMC on track to ramp 3nm chip production (in second half, 2022)
• NEWS (8/31/21): WHY THE GLOBAL CHIP SHORTAGE IS MAKING IT SO HARD TO BUY A PS5 (about the semiconductor supply chain)
• NEWS (8/18/21): Samsung unlikely to move 3nm GAA process to volume production until 2023
• NEWS (7/2/21): Micron to adopt EUV in DRAM manufacturing by 2024
• NEWS (4/16/21): TSMC to boost 5nm chip output in 2H21
• NEWS (4/8/21): Microsoft unveils liquid cooling solution for datacenters
• NEWS (3/26/21): Ball screws with smart maintenance)
• NEWS (12/15/20): TSMC to see 20% rise in 5nm shipments in first half of 2021
• NEWS (12/2/20): TSMC to roll out 3nm Plus process in 2023
• NEWS (10/16/20): TSMC expects 5nm chip sales to boost in 2021 Hiwin develops EV-use smart ball screws (another source of high demand for CPU chips: Ball screws with smart maintenance)
• NEWS (3/24/21): Intel announces US$20 billion fab expansion plans in foundry revamp
• NEWS (3/17/21): Micron to shift resources from 3D XPoint to CXL memory
    (Definintions: CXL: Compute-Express Link; 3D XPoint (aka Optane memory); CDI: Composable disaggregated infrastructure)
  • What is composable infrastructure? ("One workload could be a compute-heavy application requiring a lot of CPU power, while another could be memory-heavy. The application can grab whatever it needs at the time that it runs, and when it's done, it returns it to the pool.")
  • CXL initiative tackles memory challenges in heterogeneous computing ("In CXL, we start with CPUs, with cacheable memory both North and South, both to its own memory and to the accelerator memory. Those two pools would be part of the coherent memory pool addressable by both machines." ... "In a data center, CXL operates primarily at the node-level layer .... For the rack and row levels, the open systems Gen-Z interconnect can provide memory-semantic access to data and devices via direct-attached, switched or fabric topologies." ... "CXL and Gen-Z are very complementary.")
• NEWS (2/26/21): Highlights of the day: TSMC expanding 5nm capacity
• NEWS (10/8/20): TSMC likely to make another upward adjustment to capex outlook ... due to strong demand for 7nm and 5nm
• NEWS (9/24/20): TSMC mulling more 2nm capacity
• NEWS (9/21/20): TSMC reportedly adopts GAA transistors for 2nm chips
• NEWS (7/27/20): Intel may expand partnership with TSMC (7nm chips)

What are the largest supercomputers today?

• TOP500 Supercomputer Sites
  • NOTE: This writing is as of Fall, 2021. (Things change quickly in this area.) In terms of CPUs, we are in a three-way race among chips from Intel, AMD, and ARM (but also the IBM Power9 CPU chip on supercomputers, such as the Summit supercomputer). In the past, it was between Intel and AMD. The current largest supercomputer is Fugaku in Japan, based on 7~nanometer ARM chips (with no GPUs). China's upcoming Tianhe-3 supercomputer will also be based on ARM. Similarly, the Apple M1 chips are based on A64 ARM (with 4 big and 4 little cores). Most of the remaining top supercomputers are based on Intel or AMD, and often include NVIDIA GPUs on each node. Intel will soon be offering CPUs with discrete Intel Xe GPU chips, also to be included in the upcoming Aurora supercomputer. Meanwhile, the upcoming El Capitan supercomputer will be based on AMD CPUs and AMD GPUs, and will be used especially by the National Nuclear Security Administration (NNSA) for numclear weapon modeling.
  • Lists of Top 500 supercomputers in the world, with Top 10 on first page.
  • Some recent blogs from the TOP500 site:
    • Translating HPC Speak (an irreverent view of High Performance Computing)
    • What is the use of quantum computing without pictures or conversations? (What to do after Moore's Law ends?)
    • How To Kill A Supercomputer: Dirty Power, Cosmic Rays, and Bad Solder
• El Capitan, Frontier, and Aurora: exascale supercomputers (appearing from 2021--2023; see especially the table, lower down in this article)

Deep Learning (a motivator for high-end HPC):

Deep Learning on NVIDIA GPUs

DeepMind Beats Human Champion at Game of Go (in 2015)

"[The deep learning algorithm of] AlphaGo doesn't actually use that much hardware in play, but we needed a lot of hardware to train it and do all the different versions and have them play each other in tournaments on the cloud. That takes quite a lot of hardware to do efficiently, so we couldn't have done it in this time frame without those resources."

What are some popular programming languages today?

Relative Popularity of Different Languages

• TIOBE index (updated monthly)

Benchmark Games (Which is faster, C, Java, or Python?):
(Benchmarks are notoriously variable. Be careful about how you interpret this.)

• Benchmark "game": C versus Java
• Benchmark "game": C versus Python

Three Newer Languages (with lessons from Scheme/Java/C/C++)

• Go (widely used at Google; also the source language for Docker, a new type of lightweight virtual machine built on top of Linux containers)
• Rust (grew out of Mozilla, the developer of Firefox; may be used for a future version of Firefox)
• Scala (runs on JVM; Spark, a proposed successor to Hadoop, is built using Scala, and supports Scala, Java, and Python)

A Brief Glimpse at Some Other Assembly Languages

• Overview of Intel Assembly Language
• "Hello World" in ARM Assembly Language

Virtual memory

• Linux Memory Management Frequently Asked Questions