diff --git a/doc/7-systems/genesis.md b/doc/7-systems/genesis.md
index 283fe3ddc..bfa935845 100644
--- a/doc/7-systems/genesis.md
+++ b/doc/7-systems/genesis.md
@@ -1,6 +1,6 @@
 # Sega Genesis/Mega Drive
 
-a video game console that showed itself as the first true rival to Nintendo's video game market near-monopoly in the US during the '80's.
+a video game console that showed itself as the first true rival to Nintendo's video game market near-monopoly in the US during the '80s.
 
 this console is powered by two sound chips: the [Yamaha YM2612](ym2612.md) and [a derivative of the SN76489](sms.md).
 
diff --git a/doc/7-systems/virtual-boy.md b/doc/7-systems/virtual-boy.md
index 6aa260188..d7e5f8a6e 100644
--- a/doc/7-systems/virtual-boy.md
+++ b/doc/7-systems/virtual-boy.md
@@ -1,6 +1,6 @@
 # Virtual Boy
 
-a "portable" video game console made by Nintendo in the '90's.
+a "portable" video game console made by Nintendo in the '90s.
 
 it supposedly was the beginning of virtual reality... nah, instead it failed to sell well because you use it for 15 minutes and then you get a headache.
 
diff --git a/src/engine/sysDef.cpp b/src/engine/sysDef.cpp
index aee338493..b9c37d890 100644
--- a/src/engine/sysDef.cpp
+++ b/src/engine/sysDef.cpp
@@ -1,4 +1,4 @@
-/**
+'/**
  * Furnace Tracker - multi-system chiptune tracker
  * Copyright (C) 2021-2023 tildearrow and contributors
  *
@@ -674,7 +674,7 @@ void DivEngine::registerSystems() {
 
   sysDefs[DIV_SYSTEM_PCE]=new DivSysDef(
     "PC Engine/TurboGrafx-16", NULL, 0x05, 0x05, 6, false, true, 0x161, false, 1U<<DIV_SAMPLE_DEPTH_8BIT,
-    "an '80's game console with a wavetable sound chip, popular in Japan.",
+    "an '80s game console with a wavetable sound chip, popular in Japan.",
     {"Channel 1", "Channel 2", "Channel 3", "Channel 4", "Channel 5", "Channel 6"},
     {"CH1", "CH2", "CH3", "CH4", "CH5", "CH6"},
     {DIV_CH_WAVE, DIV_CH_WAVE, DIV_CH_WAVE, DIV_CH_WAVE, DIV_CH_WAVE, DIV_CH_WAVE},
@@ -691,7 +691,7 @@ void DivEngine::registerSystems() {
 
   sysDefs[DIV_SYSTEM_NES]=new DivSysDef(
     "NES (Ricoh 2A03)", NULL, 0x06, 0x06, 5, false, true, 0x161, false, (1U<<DIV_SAMPLE_DEPTH_1BIT_DPCM)|(1U<<DIV_SAMPLE_DEPTH_8BIT),
-    "also known as Famicom in Japan, it's the most well-known game console of the '80's.",
+    "also known as Famicom in Japan, it's the most well-known game console of the '80s.",
     {"Pulse 1", "Pulse 2", "Triangle", "Noise", "DPCM"},
     {"S1", "S2", "TR", "NO", "DMC"},
     {DIV_CH_PULSE, DIV_CH_PULSE, DIV_CH_WAVE, DIV_CH_NOISE, DIV_CH_PCM},
@@ -792,7 +792,7 @@ void DivEngine::registerSystems() {
 
   sysDefs[DIV_SYSTEM_AMIGA]=new DivSysDef(
     "Amiga", NULL, 0x81, 0, 4, false, true, 0, false, 1U<<DIV_SAMPLE_DEPTH_8BIT,
-    "a computer from the '80's with full sampling capabilities, giving it a sound ahead of its time.",
+    "a computer from the '80s with full sampling capabilities, giving it a sound ahead of its time.",
     {"Channel 1", "Channel 2", "Channel 3", "Channel 4"},
     {"CH1", "CH2", "CH3", "CH4"},
     {DIV_CH_PCM, DIV_CH_PCM, DIV_CH_PCM, DIV_CH_PCM},