A Defrag Simulator In Your Browser

September 1, 2026 by Zoe Skyforest 30 Comments

Disk Defragmenter was a wonderful utility that Microsoft included with Windows back in the day. Back then, you’d use it to theoretically speed up disk access. Today, you can run a fun simulation right in your browser thanks to [Dennis Morello].

The theory behind defragmenting hard disks was simple. Your hard drive would store data on spinning magnetic platters. Sometimes, a given file or group of files would end up with their different parts scattered across different parts of a platter, or even multiple platters, as the file system tried to slot everything into the space available over time. On a drive accessed with a literal physical mechanism, this fragmentation of files across multiple areas of a disk could cause functional read speeds to drop. To solve this, you could defragment the drive, wherein a utility would grab disparate bits of different files and put them physically closer together on the drive platters, such that the read heads could access larger contiguous chunks of files more easily.

[Dennis’s] project does none of that. It just simulates the visuals and sound of running Microsoft’s disk defragmenter tool from Windows 98. It’s got the little rows of squares that get rearranged, blue for unoptimized data, dark blue for defragmented data, and white boxes for free space. It’s got the progress bar along the bottom, too, and a nice little simulated sound of a hard disk ca-chunking away as it shuffles little bits of data to and fro. This was the kind of thing you’d do on a rainy Saturday afternoon in the 1990s, just watching your PC make itself a few percent faster while you drank coffee and wondered if your ex-wife Jacinta was ever coming back. She never did, but you did notice that Age of Empires II loaded a fair bit quicker after you ran a full defrag on your main drive. Sometimes, that’s as good as it gets.

Modern file systems are better at managing issues like fragmentation, and the virtually instant seek speeds of solid-state drives essentially eliminated the need for defragmentation for good. Still, it’s fun to visit an ancient tool from yesteryear and remember what it meant to us way back when. Maybe you could give Jacinta a call, too, just for old times sake, and discuss that time a Janet Jackson song started crashing brand-new Windows laptops right out of the box…

Microsoft Finally Ups FAT32 Size Limit

April 17, 2026 by Zoe Skyforest 39 Comments

You probably don’t spend a lot of time using the FAT32 file system anymore, since it’s thoroughly been superseded many times over. Even so, Microsoft has seen fit to deliver an upgrade for FAT32 for the latest Windows 11 Insider Preview build. Finally, the stock Windows tools will let you format a FAT32 drive up to 2 TB instead of locking you to a 32 GB maximum!

The size limit was never baked into the FAT32 spec itself. With a 32-bit field for counting sectors, the file system supports up to 2 TB volumes with 512-byte sectors. However, as explained by former Microsoft developer [Dave Plummer], it just so happened that the 32 GB limit came about because of a random decision made when slapping together the Format dialogue box over 30 years ago.

The pending change was first announced in 2024, affecting the command line format tool as well. It’s actually been possible to create larger FAT32 volumes for some time, you just couldn’t easily do it with Microsoft’s standard formatting tools.

FAT32 is still a terrible file system to use in 2026, mostly because it has a hard limit on file size that tops out at 4 GB. It’ll ruin your life if you’re shooting HD or 4K video. We often don’t spend a lot of time musing over file systems in detail, but they’re right at the heart of everything we do on our computers on a daily basis. Sometimes, it bears thinking about!

C Project Turns Into Full-Fledged OS

October 14, 2025 by Bryan Cockfield 7 Comments

While some of us may have learned C in order to interact with embedded electronics or deep with computing hardware of some sort, others learn C for the challenge alone. Compared to newer languages like Python there’s a lot that C leaves up to the programmer that can be incredibly daunting. At the beginning of the year [Ethan] set out with a goal of learning C for its own sake and ended up with a working operating system from scratch programmed in not only C but Assembly as well.

[Ethan] calls his project Moderate Overdose of System Eccentricity, or MooseOS. Original programming and testing was done in QEMU on a Mac where he was able to build all of the core components of the operating system one-by-one including a kernel, a basic filesystem, and drivers for PS/2 peripherals as well as 320×200 VGA video. It also includes a dock-based GUI with design cues from operating systems like Macintosh System 1. From that GUI users can launch a few applications, from a text editor, a file explorer, or a terminal. There’s plenty of additional information about this OS on his GitHub page as well as a separate blog post.

The project didn’t stay confined to the QEMU virtual machine either. A friend of his was throwing away a 2009-era desktop which [Ethan] quickly grabbed to test his operating system on bare metal. There was just one fault that the real hardware threw that QEMU never did, but with a bit of troubleshooting it was able to run. He also notes that this was inspired by a wiki called OSDev which, although a bit dated now, is a great place to go to learn about the fundamentals of operating systems. We’d also recommend checking out this project that performs a similar task but on the RISC-V instruction set instead.

Make A Secret File Stash In The Slack Space

February 10, 2025 by Donald Papp 15 Comments

Disk space is allocated in clusters of a certain size. When a file is written to disk and the file size is smaller than the cluster(s) allocated for it, there is an unused portion of varying size between the end of the file’s data and the end of the allocated clusters. This unused space is the slack space, it’s perfectly normal, and [Zachary Parish] had an idea to write a tool to hide data in it.

The demo uses a usb drive, using the slack space from decoy files to read and write data.

[Zachary]’s tool is in Python and can map available slack space and perform read and write operations on it, treating the disparate locations as a single unified whole in which to store arbitrary files. A little tar and gzip even helps makes things more efficient in the process.

There’s a whole demo implemented on Linux using a usb drive with some decoy files to maximize the slack space, and you can watch it in action in the video embedded below. It’s certainly more practical than hiding data in a podcast!

Note that this is just a demo of the concept. The approach does have potential for handling secret data, but [Zachary] points out that there are — from a serious data forensics point of view– a number of shortcomings in its current form. For example, the way the tool currently structures and handles data makes it quite obvious that something is going on in the slack space.

[Zachary] created this a few years ago and has some ideas about how to address those shortcomings and evolve the tool, so if you have ideas of your own or just want to try it out, the slack_hider GitHub repository is where you want to go.

Continue reading “Make A Secret File Stash In The Slack Space” →

Google Drive Now Bootable

July 2, 2024 by Bryan Cockfield 22 Comments

USB drives are incredibly useful, both storing files for transport between different computers and for creating bootable drives that let us use or install other operating systems on our computers. While online file storage systems like Dropbox and Google Drive have taken over a large percentage of the former task from USB drives, they have not been able to act as bootable media, ensuring that each of us have a few jump drives lying around. That might not be the case anymore, though, as this guide is the first we know of to be able to use Google Drive to boot to a Linux system.

Unlike the tried-and-true jump drive methods, however, this process is not straightforward at all. It relies on two keys, the first of which is FUSE which allows a filesystem to be created in userspace. The second is exploiting a step in boot process of Linux systems where the kernel unpacks a temporary filesystem, called initramfs, in order to load the real filesystem. Normally a user doesn’t interact much with this step, but that doesn’t mean it’s impossible. A tool called dracut allows using an existing Linux installation to build a custom initramfs and in this case, the custom initramfs is built to include the proper support for both networking and FUSE.

The proof of concept in this demonstration originally ran in a container, using an existing project called google-drive-ocamlfuse to interact with Google Drive itself. From there, after sorting out some issues with root access, networking, malfunctioning symlinks, and various timeouts on the (perhaps predictably) slow system, the whole contraption was moved over to a laptop so it could be tested on real hardware. Everything runs, and although the original creator of this behemoth admits it is a bit “silly” they note that there may be some real-world use cases for something like this. We still won’t expect everyone to throw out their jump drives anytime soon, though. If you’re not feeling like your Linux skills are up to the challenge of something like this, we’d recommend you start with our own [Al Williams]’s Linux Fu series.

Analysing National Budgets With File System Tools

April 15, 2019 by Zoe Skyforest 20 Comments

Understanding a national budget can be difficult, with political interests and distorted talking points obscuring the truth. There’s no substitute for diving into the hard data yourself, but it can be difficult to know where to start. [D. Scott Williamson] wanted to do just that, and took an unconventional path – using file system tools to analyse the 2019 US budget.

The basic idea is simple. A file is created for every line item on the budget, and this file is filled with a $ for every million dollars that item costs. These files are sorted into folders for the relevant bureaus and agencies responsible, creating a Fiscal File System representation of the entire budget. The file system can then be analysed with standard tools to get a look at the overall make up of the budget – in this case, WinDirStat does a particularly good job.

It’s a novel way to go about budget analysis, and fills a gap in the market now that Time Plots aren’t producing their Death and Taxes infographics anymore. Pre-cooked file systems covering budgets back to 1977 are available for your perusal, should you need to investigate how things have changed over time.

Unsurprisingly, we haven’t covered the national budget before, but we’re always down to talk file systems.

ULTIMATE – A Useful Tool For File System Hacking

December 17, 2018 by Zoe Skyforest 23 Comments

Whether you’re at the hobbyist level or a professional, if you’re working on code for operating systems or file systems, tools can make or break the job. [Ben Lunt] is an enthusiast hacker himself, and found that over time, a series of useful utilities had proliferated beyond reasonable management. It was time to solve the problem – enter ULTIMATE.

ULTIMATE is a combination of a wide swathe of file system hacking tools that [Ben] had developed over the preceding years. Capable of dealing with most FAT variants, Ext4, ISO, [Ben]’s own FYS FS as well as other Linux ephemera, it enables a wide variety of common tasks to be executed from within a single program.

Capabilities of the tool are wide ranging. Files can be inserted into and removed from image files, boot records can be altered, and there’s even the ability to tinker with GPTs for UEFI-based systems. [Ben] has also experimented with the concept of the eMBR – an extended Master Boot Record with greater functionality for larger, modern hard drives.

ULTIMATE is a testament to [Ben]’s broad file system knowledge, and could likely serve useful to many hackers in the file system and OS community. Just be cautious, though – the software is still in an early stage of development. If you’re just getting started in this particular realm of tinkering, take our primer on file system forensics.