diff --git a/readme.txt b/readme.txt
index 77c3157..2c72af4 100644
--- a/readme.txt
+++ b/readme.txt
@@ -11,16 +11,17 @@ Calcite is very much alpha software. Do not expect it to do anything useful.
 
 === Building
 
-Calcite requires some dependencies before it can be built:
+Calcite requires some software to be installed before it can be built:
  * curl
  * GCC (Any C compiler supporting both C99 and C23 should work.)
  * GNU Binutils (Specifically, "ld" is used to link the kernel.)
  * GNU Make (I don't think I have used any GNU extensions.)
+ * GNU tar (Any POSIX tar should be fine.)
  * GNU xorriso
  * NASM
 
 On Debian, it is sufficient to run this command:
-  apt install binutils curl gcc make nasm xorriso
+  apt install binutils curl gcc make nasm tar xorriso
 
 To build Calcite, first run "sh get-dependencies.sh", then run "make".
 This will build a disk image at "build/disk.iso" that can be booted
@@ -28,7 +29,7 @@ with either BIOS or UEFI.
 
 === Debugging
 
-Once Calcite has been built, some more dependencies are required to debug it:
+Once Calcite has been built, some more software is required to debug it:
  * GNU's GDB
  * QEMU, including the x86_64 system