Presentation given on Techweek context for Junior Dev developers community at Tauranga, New Zealand.

1. Coding on a 40 year
old computer to
understand today’s
technology
A journey to madness and its way back

2. About me
Matías Iacono

3. Why coding in an old computer?
- Because you can.
- Because is a challenge.
- Because... code quality!

4. Some history first!

5. Sinclair ZX 81
- 1 KB of memory
- … and that’s all!

6. Sinclair ZX
Spectrum
- 16 KB of memory (48 KB to 128 KB for later
models).
- Basic as official included
programing language.
- Assembler for the braves!

7. Why this is a challenge?
8 GB of RAM from a
standard computer
today
48 KB of RAM
= .23 km

8. That is not all!

9. Processor speed
ZX80 = 3.5MHz
Intel i5 = 2.9GHz
~= 0.01015 the power of
an i5

10. Coding!

11. A simple game
(of 4400 lines)
ld hl,msgdat
ld a,b
dec a
cp 32
jr nc,iscrl0
A for...loop to decrease A
and jump to other part of the
code if A is equals to 32.

12. Demo time!

13. Why is important?

14. Every bit matters!

15. Speed and
quality
What the consumer wants
- Good code is easy to maintain
(Cyclomatic complexity).
- Fast code increase customer
quality perception.
- Good code is less prone to bugs.
- Good code cost less!

16. Real life examples

17. C# developers and strings
https://github.com/dotnet/coreclr/blob/19a88d8a92e08c8506f6e69c3964dc77329c108a/src/vm/amd
64/JitHelpers_Slow.asm#L274-L322
https://github.com/dotnet/coreclr/blob/19a88d8a92e08c8506f6e69c3964dc77329c108a/src/mscorlib/sr
c/System/String.cs#L963-L975
[System.Security.SecurityCritical] // auto-generated
[MethodImplAttribute(MethodImplOptions.InternalCall)]
internal extern static String FastAllocateString(int length);

18. More strings

19. Loading speed in mobile

20. The “way back”

21. Why coding for an old computer?
- Gives you a different vision of the available resources in your system (They are
precious).
- Force you to think more creative ways of coding.
- Helps you to create better code.
- Will help you to spend less time and money fixing bugs.
- Will make your customer happier.

22. Thanks!