• Stars
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    524
  • Rank 84,541 (Top 2 %)
  • Language
    Assembly
  • Created over 5 years ago
  • Updated 8 months ago

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Repository Details

Here I share the code of my CV, which is also a bootable bootloader :)

My curriculum is also a bootloader

ScreenShot

What?

The PDF attached in this repository is both a working PDF of my CV and a custom bootloader created by me to impress technical recruiters. Check the discussion in HN.

How?

I wrote a tiny bootloader of 1018 bytes. Then I just copy the first bytes of my bootloader at the beginning of my CV and that is it, a working PDF and bootloader.

Can I try it?

Sure! You can do so by two means, in real hardware (I spend a lot of time making it compatible) or in an emulated environment.

Real hardware

NOTE: All the data on the USB will be lost, please make sure you have a backup before continuing.

Windows

You can use Win32 Disk Imager and use the PDF as the input image.

To recover your USB just right click on it and format normally.

Linux

NOTE: Please be very careful with this command. If you select the wrong drive you will lose data.

Get a USB, check the device name (you can use df -h) and do:

sudo dd if=pablo_jimenez_mateo_cv.pdf of=/dev/sdX bs=512 count=2880
sync

where X is your device.

To recover your USB just use gparted.

Emulated environment

Qemu
qemu-system-i386 -drive format=raw,file=pablo_jimenez_mateo_cv.pdf
Bochs:

Create a bochsrc.txt file with this contents:

megs: 32
romimage: file=/usr/share/bochs/BIOS-bochs-latest, address=0xfffe0000
vgaromimage: file=/usr/share/bochs/VGABIOS-lgpl-latest
floppya: 1_44=pablo_jimenez_mateo_cv.pdf, status=inserted
boot: a
log: bochsout.txt
mouse: enabled=0
display_library: x, options="gui_debug"

And then execute bochs as follows:

bochs -f bochsrc.txt

Compiling from source

nasm boot.asm -o boot.bin

Get your vanilla PDF, CV_english.pdf in this example, and do:

qpdf --stream-data=uncompress --object-streams=disable CV_english.pdf uncompressed.pdf
python3 patch.py

FAQ

  • But why?

    As a learning experience. I realized that I had no practical knowledge on how the booting process works, and also my assembly was a little bit rusty. This is a project I really enjoyed, although it was a little bit overwhelming at some points.

  • Can you explain how?

    I have tried my best to comment the code thoroughly, including my optimization decisions as well as the encoding of the sprites. I have also linked to a couple of Stackoverflow answers for deeper understanding.

  • But now your PDF is bigger!

    Yes, but 1018 bytes bigger or less than 0.01% bigger. For comparison, the gif in this readme is 2778093 bytes or 2728,97 times bigger! The Firefox icon is 8532 bytes, 8.38 times bigger!

This program is licensed under Creative commons Attribution 3.0 Unported, more info : http://creativecommons.org/licenses/by/3.0/deed.en_US