diff --git a/src/crystal/system.cr b/src/crystal/system.cr
deleted file mode 100644
index 5ef653370048..000000000000
--- a/src/crystal/system.cr
+++ /dev/null
@@ -1,18 +0,0 @@
-# :nodoc:
-module Crystal::System
-  # Returns the hostname
-  # def self.hostname
-
-  # Returns the number of logical processors available to the system.
-  #
-  # def self.cpu_count
-end
-
-require "./system/unix/hostname"
-
-{% if flag?(:freebsd) || flag?(:openbsd) %}
-  require "./system/unix/sysctl_cpucount"
-{% else %}
-  # TODO: restrict on flag?(:unix) after crystal > 0.22.0 is released
-  require "./system/unix/sysconf_cpucount"
-{% end %}
diff --git a/src/crystal/system/random.cr b/src/crystal/system/random.cr
deleted file mode 100644
index b98458c88622..000000000000
--- a/src/crystal/system/random.cr
+++ /dev/null
@@ -1,20 +0,0 @@
-module Crystal::System::Random
-  # Fills *buffer* with random bytes from a secure source.
-  # def self.random_bytes(buffer : Bytes) : Nil
-
-  # Returns a random unsigned integer from a secure source. Implementations
-  # may choose the integer size to return based on what the system source
-  # provides. They may choose to return a single byte (UInt8) in which case
-  # `::Random` will prefer `#random_bytes` to read as many bytes as required
-  # at once, avoiding multiple reads or reading too many bytes.
-  # def self.next_u
-end
-
-{% if flag?(:linux) %}
-  require "./unix/getrandom"
-{% elsif flag?(:openbsd) %}
-  require "./unix/arc4random"
-{% else %}
-  # TODO: restrict on flag?(:unix) after crystal > 0.22.0 is released
-  require "./unix/urandom"
-{% end %}
diff --git a/src/crystal/system/time.cr b/src/crystal/system/time.cr
deleted file mode 100644
index b0e76f43b8c2..000000000000
--- a/src/crystal/system/time.cr
+++ /dev/null
@@ -1,11 +0,0 @@
-module Crystal::System::Time
-  # Returns the number of seconds that you must add to UTC to get local time.
-  # *seconds* are measured from `0001-01-01 00:00:00`.
-  # def self.compute_utc_offset(seconds : Int64) : Int64
-
-  # Returns the current UTC time measured in `{seconds, tenth_microsecond}`
-  # since `0001-01-01 00:00:00`.
-  # def self.compute_utc_second_and_tenth_microsecond : {Int64, Int64}
-end
-
-require "./unix/time"
diff --git a/src/platform_specific/random.cr b/src/platform_specific/random.cr
new file mode 100644
index 000000000000..7561c93dd849
--- /dev/null
+++ b/src/platform_specific/random.cr
@@ -0,0 +1,8 @@
+{% if flag?(:linux) %}
+  require "./unix/getrandom"
+{% elsif flag?(:openbsd) %}
+  require "./unix/arc4random"
+{% else %}
+  # TODO: restrict on flag?(:unix) after crystal > 0.22.0 is released
+  require "./unix/urandom"
+{% end %}
diff --git a/src/platform_specific/system.cr b/src/platform_specific/system.cr
new file mode 100644
index 000000000000..c41ae344ed36
--- /dev/null
+++ b/src/platform_specific/system.cr
@@ -0,0 +1,8 @@
+require "./unix/hostname"
+
+{% if flag?(:freebsd) || flag?(:openbsd) %}
+  require "./unix/sysctl_cpucount"
+{% else %}
+  # TODO: restrict on flag?(:unix) after crystal > 0.22.0 is released
+  require "./unix/sysconf_cpucount"
+{% end %}
diff --git a/src/platform_specific/time.cr b/src/platform_specific/time.cr
new file mode 100644
index 000000000000..f35bff5a95a9
--- /dev/null
+++ b/src/platform_specific/time.cr
@@ -0,0 +1 @@
+require "./unix/time"
diff --git a/src/crystal/system/unix/arc4random.cr b/src/platform_specific/unix/arc4random.cr
similarity index 63%
rename from src/crystal/system/unix/arc4random.cr
rename to src/platform_specific/unix/arc4random.cr
index 863c0978eb3f..412566d995be 100644
--- a/src/crystal/system/unix/arc4random.cr
+++ b/src/platform_specific/unix/arc4random.cr
@@ -2,11 +2,11 @@
 
 require "c/stdlib"
 
-module Crystal::System::Random
-  # Fills *buffer* with random bytes using arc4random.
-  #
-  # NOTE: only secure on OpenBSD and CloudABI
+module Random::System
   def self.random_bytes(buffer : Bytes) : Nil
+    # Fills *buffer* with random bytes using arc4random.
+    #
+    # NOTE: only secure on OpenBSD and CloudABI
     LibC.arc4random_buf(buffer.to_unsafe.as(Void*), buffer.size)
   end
 
diff --git a/src/crystal/system/unix/getrandom.cr b/src/platform_specific/unix/getrandom.cr
similarity index 96%
rename from src/crystal/system/unix/getrandom.cr
rename to src/platform_specific/unix/getrandom.cr
index 616345173347..15409f318287 100644
--- a/src/crystal/system/unix/getrandom.cr
+++ b/src/platform_specific/unix/getrandom.cr
@@ -3,7 +3,7 @@
 require "c/unistd"
 require "c/sys/syscall"
 
-module Crystal::System::Random
+module Random::System
   @@initialized = false
   @@getrandom_available = false
   @@urandom : File?
@@ -23,8 +23,8 @@ module Crystal::System::Random
     end
   end
 
-  # Reads n random bytes using the Linux `getrandom(2)` syscall.
   def self.random_bytes(buf : Bytes) : Nil
+    # Reads n random bytes using the Linux `getrandom(2)` syscall.
     init unless @@initialized
 
     if @@getrandom_available
diff --git a/src/crystal/system/unix/hostname.cr b/src/platform_specific/unix/hostname.cr
similarity index 91%
rename from src/crystal/system/unix/hostname.cr
rename to src/platform_specific/unix/hostname.cr
index e803ef514185..b497dce7efd5 100644
--- a/src/crystal/system/unix/hostname.cr
+++ b/src/platform_specific/unix/hostname.cr
@@ -1,6 +1,6 @@
 require "c/unistd"
 
-module Crystal::System
+module System
   def self.hostname
     String.new(255) do |buffer|
       unless LibC.gethostname(buffer, LibC::SizeT.new(255)) == 0
diff --git a/src/crystal/system/unix/sysconf_cpucount.cr b/src/platform_specific/unix/sysconf_cpucount.cr
similarity index 86%
rename from src/crystal/system/unix/sysconf_cpucount.cr
rename to src/platform_specific/unix/sysconf_cpucount.cr
index 58eed376da5c..4a615e78dca7 100644
--- a/src/crystal/system/unix/sysconf_cpucount.cr
+++ b/src/platform_specific/unix/sysconf_cpucount.cr
@@ -2,7 +2,7 @@
 
 require "c/unistd"
 
-module Crystal::System
+module System
   def self.cpu_count
     LibC.sysconf(LibC::SC_NPROCESSORS_ONLN)
   end
diff --git a/src/crystal/system/unix/sysctl_cpucount.cr b/src/platform_specific/unix/sysctl_cpucount.cr
similarity index 93%
rename from src/crystal/system/unix/sysctl_cpucount.cr
rename to src/platform_specific/unix/sysctl_cpucount.cr
index f5646b1b0377..8f92e8685a9e 100644
--- a/src/crystal/system/unix/sysctl_cpucount.cr
+++ b/src/platform_specific/unix/sysctl_cpucount.cr
@@ -2,7 +2,7 @@
 
 require "c/sysctl"
 
-module Crystal::System
+module System
   def self.cpu_count
     mib = Int32[LibC::CTL_HW, LibC::HW_NCPU]
     ncpus = 0
diff --git a/src/crystal/system/unix/time.cr b/src/platform_specific/unix/time.cr
similarity index 88%
rename from src/crystal/system/unix/time.cr
rename to src/platform_specific/unix/time.cr
index 2017c200e78e..4615ae2276d5 100644
--- a/src/crystal/system/unix/time.cr
+++ b/src/platform_specific/unix/time.cr
@@ -1,10 +1,10 @@
 require "c/sys/time"
 require "c/time"
 
-module Crystal::System::Time
+struct Time
   UnixEpochInSeconds = 62135596800_i64
 
-  def self.compute_utc_offset(seconds : Int64) : Int64
+  private def self.compute_utc_offset(seconds : Int64) : Int64
     LibC.tzset
     offset = nil
 
@@ -26,7 +26,7 @@ module Crystal::System::Time
     offset
   end
 
-  def self.compute_utc_second_and_tenth_microsecond : {Int64, Int64}
+  private def self.compute_utc_second_and_tenth_microsecond : {Int64, Int64}
     {% if LibC.methods.includes?("clock_gettime".id) %}
       ret = LibC.clock_gettime(LibC::CLOCK_REALTIME, out timespec)
       raise Errno.new("clock_gettime") unless ret == 0
diff --git a/src/crystal/system/unix/urandom.cr b/src/platform_specific/unix/urandom.cr
similarity index 96%
rename from src/crystal/system/unix/urandom.cr
rename to src/platform_specific/unix/urandom.cr
index 424641890d40..0843013078d7 100644
--- a/src/crystal/system/unix/urandom.cr
+++ b/src/platform_specific/unix/urandom.cr
@@ -1,7 +1,7 @@
 # TODO: replace with `flag?(:unix) && !flag?(:openbsd) && !flag?(:linux)` after crystal > 0.22.0 is released
 {% skip_file() if flag?(:openbsd) && flag?(:linux) %}
 
-module Crystal::System::Random
+module Random::System
   @@initialized = false
   @@urandom : File?
 
diff --git a/src/random/isaac.cr b/src/random/isaac.cr
index 03b5f7a994bf..54ead6a2c0d5 100644
--- a/src/random/isaac.cr
+++ b/src/random/isaac.cr
@@ -1,4 +1,4 @@
-require "crystal/system/random"
+require "random/system"
 
 # (c) Bob Jenkins, March 1996, Public Domain
 # You may use this code in any way you wish, and it is free.  No warrantee.
@@ -17,7 +17,7 @@ class Random::ISAAC
   private def random_seeds
     result = uninitialized Seeds
     result_slice = result.unsafe_as(StaticArray(UInt8, sizeof(Seeds))).to_slice
-    Crystal::System::Random.random_bytes(result_slice)
+    Random::System.random_bytes(result_slice)
     result
   end
 
diff --git a/src/random/system.cr b/src/random/system.cr
index 54fdbebfd440..f12411ef7b05 100644
--- a/src/random/system.cr
+++ b/src/random/system.cr
@@ -1,5 +1,3 @@
-require "crystal/system/random"
-
 # Generates random numbers from a secure source of the system.
 #
 # For example `arc4random` is used on OpenBSD, whereas on Linux it uses
@@ -12,17 +10,26 @@ require "crystal/system/random"
 # ```
 module Random::System
   extend Random
-  extend self
 
-  def next_u
-    Crystal::System::Random.next_u
+  # Fills *buffer* with random bytes from a secure source.
+  def self.random_bytes(buffer : Bytes) : Nil
+    {% raise "Not implemented for this system" %}
+  end
+
+  # Returns a random unsigned integer from a secure source. Implementations
+  # may choose the integer size to return based on what the system source
+  # provides. They may choose to return a single byte (UInt8) in which case
+  # `::Random` will prefer `#random_bytes` to read as many bytes as required
+  # at once, avoiding multiple reads or reading too many bytes.
+  def self.next_u
+    {% raise "Not implemented for this system" %}
   end
 
   {% for type in [UInt8, UInt16, UInt32, UInt64] %}
     # Generates a random integer of a given type. The number of bytes to
     # generate can be limited; by default it will generate as many bytes as
     # needed to fill the integer size.
-    private def rand_type(type : {{type}}.class, needed_parts = nil) : {{type}}
+    private def self.rand_type(type : {{type}}.class, needed_parts = nil) : {{type}}
       needed_bytes =
         if needed_parts
           needed_parts * sizeof(typeof(next_u))
@@ -34,22 +41,24 @@ module Random::System
 
       if needed_bytes < sizeof({{type}})
         bytes = Slice.new(buf.to_unsafe, needed_bytes)
-        Crystal::System::Random.random_bytes(bytes)
+        random_bytes(bytes)
 
         bytes.reduce({{type}}.new(0)) do |result, byte|
           (result << 8) | byte
         end
       else
-        Crystal::System::Random.random_bytes(buf.to_slice)
+        random_bytes(buf.to_slice)
         buf.to_unsafe.as({{type}}*).value
       end
     end
   {% end %}
 
   {% for type in [Int8, Int16, Int32, Int64] %}
-    private def rand_type(type : {{type}}.class, needed_bytes = sizeof({{type}})) : {{type}}
+    private def self.rand_type(type : {{type}}.class, needed_bytes = sizeof({{type}})) : {{type}}
       result = rand_type({{"U#{type}".id}}, needed_bytes)
       {{type}}.new(result)
     end
   {% end %}
 end
+
+require "platform_specific/random"
diff --git a/src/secure_random.cr b/src/secure_random.cr
index d713f1a95a38..7867bb59681a 100644
--- a/src/secure_random.cr
+++ b/src/secure_random.cr
@@ -1,5 +1,4 @@
 require "base64"
-require "crystal/system/random"
 
 # The `SecureRandom` module is an interface for creating cryptography secure
 # random values in different formats.
@@ -74,7 +73,7 @@ module SecureRandom
   # slice                            # => [217, 118, 38, 196]
   # ```
   def self.random_bytes(buf : Bytes) : Nil
-    Crystal::System::Random.random_bytes(buf)
+    Random::System.random_bytes(buf)
   end
 
   # Generates a UUID (Universally Unique Identifier).
diff --git a/src/system.cr b/src/system.cr
index 6746651caeb0..1b8198cf1680 100644
--- a/src/system.cr
+++ b/src/system.cr
@@ -1,5 +1,3 @@
-require "crystal/system"
-
 module System
   # Returns the hostname.
   #
@@ -11,7 +9,7 @@ module System
   # System.hostname # => "host.example.org"
   # ```
   def self.hostname
-    Crystal::System.hostname
+    {% raise "Not implemented for this system" %}
   end
 
   # Returns the number of logical processors available to the system.
@@ -20,6 +18,8 @@ module System
   # System.cpu_count # => 4
   # ```
   def self.cpu_count
-    Crystal::System.cpu_count
+    {% raise "Not implemented for this system" %}
   end
 end
+
+require "platform_specific/system"
diff --git a/src/time.cr b/src/time.cr
index 9d2c270f1148..737d8d3db082 100644
--- a/src/time.cr
+++ b/src/time.cr
@@ -1,5 +1,3 @@
-require "crystal/system/time"
-
 # `Time` represents an instance in time. Here are some examples:
 #
 # ### Basic Usage
@@ -600,12 +598,25 @@ struct Time
   end
 
   private def self.compute_offset(second)
-    Crystal::System::Time.compute_utc_offset(second) / 60 * Span::TicksPerMinute
+    compute_utc_offset(second) / 60 * Span::TicksPerMinute
   end
 
   private def self.compute_second_and_tenth_microsecond
-    Crystal::System::Time.compute_utc_second_and_tenth_microsecond
+    compute_utc_second_and_tenth_microsecond
+  end
+
+  # Returns the number of seconds that you must add to UTC to get local time.
+  # *seconds* are measured from `0001-01-01 00:00:00`.
+  private def self.compute_utc_offset(seconds : Int64) : Int64
+    {% raise "Not implemented for this system" %}
+  end
+
+  # Returns the current UTC time measured in `{seconds, tenth_microsecond}`
+  # since `0001-01-01 00:00:00`.
+  private def self.compute_utc_second_and_tenth_microsecond : {Int64, Int64}
+    {% raise "Not implemented for this system" %}
   end
 end
 
 require "./time/**"
+require "platform_specific/time"