From b127d7b130a15121c50ec258f2abb280c6e6e7d0 Mon Sep 17 00:00:00 2001
From: JTEpic <jjrocks2006@att.net>
Date: Sun, 25 May 2025 13:25:36 -0500
Subject: [PATCH] Fixes to bootloader and linker

---
 .../Part_3/bootloader/Makefile                |   5 +++++
 .../Part_3/bootloader/bin/boot.bin            | Bin 512 -> 512 bytes
 .../Part_3/bootloader/bin/kernel.bin          | Bin 518 -> 541 bytes
 .../Part_3/bootloader/bin/os.bin              | Bin 5126 -> 5149 bytes
 .../Part_3/bootloader/build/completeKernel.o  | Bin 2928 -> 3212 bytes
 .../Part_3/bootloader/build/kernel.asm.o      | Bin 1936 -> 1968 bytes
 .../Part_3/bootloader/build/kernel.o          | Bin 1676 -> 2032 bytes
 .../Part_3/bootloader/src/boot.asm            |  16 +++++++++++++++-
 .../Part_3/bootloader/src/kernel.asm          |   4 ++--
 .../Part_3/bootloader/src/kernel.c            |   6 +++++-
 .../Part_3/bootloader/src/kernel.h            |   4 ++--
 .../Part_3/bootloader/src/linkerScript.ld     |   8 ++++----
 12 files changed, 33 insertions(+), 10 deletions(-)
 mode change 100644 => 100755 How_to_write_a_bootloader/Part_3/bootloader/bin/kernel.bin

diff --git a/How_to_write_a_bootloader/Part_3/bootloader/Makefile b/How_to_write_a_bootloader/Part_3/bootloader/Makefile
index 021f0d5..9661f70 100644
--- a/How_to_write_a_bootloader/Part_3/bootloader/Makefile
+++ b/How_to_write_a_bootloader/Part_3/bootloader/Makefile
@@ -12,6 +12,11 @@ all:
 	dd if=./bin/kernel.bin >> ./bin/os.bin
 	dd if=/dev/zero bs=512 count=8 >> ./bin/os.bin
 
+qemu:
+	# Use 32 bit qemu when using debugger on this 32 bit OS
+	qemu-system-x86_64 -hda ./bin/os.bin
+	#qemu-system-i386 -hda ./bin/os.bin
+
 clean:
 	rm -f ./bin/boot.bin
 	rm -f ./bin/kernel.bin
diff --git a/How_to_write_a_bootloader/Part_3/bootloader/bin/boot.bin b/How_to_write_a_bootloader/Part_3/bootloader/bin/boot.bin
index 8857245c01c838fcf9e455b962e7e5d93fe2e726..96d39b12fc0d3323ed394d98c5fc5e16d92d7945 100644
GIT binary patch
delta 83
zcmV-Z0IdIj1b_q_`nUi9j@XXCj?laSeEYNjumjByy8sZ5!@B?gkr5OOSbPs4zzhKo
pBEafikue?tK#@=$621Tc0RX=M01yDV01yBG{PU!-ZgT+wRjL<e9I^la

delta 72
zcmV-O0Jr~u1b_rF`nUi9j@XXCj?laSeEYiq5VioafUyF#0JH+I2+b366Z#JU7EOE)
eAixX(4<f+oQ;|F#0X30Z9<hsa0g<2`0#&Ld+#6f~

diff --git a/How_to_write_a_bootloader/Part_3/bootloader/bin/kernel.bin b/How_to_write_a_bootloader/Part_3/bootloader/bin/kernel.bin
old mode 100644
new mode 100755
index cdb8dcef7bae920b49f50fd45f38111bb172b0bf..02706a7756e4985c11b2ceb99314117817914194
GIT binary patch
literal 541
zcmaFylaYbp^*@GDFcL!`wDW268-e4le;69L8M<Bn9AoeRlFbL0jxl6TIC&TV>Ae!y

literal 518
WcmaFyn~`A@jNA|i?R+{R_Amh7`UO}3

diff --git a/How_to_write_a_bootloader/Part_3/bootloader/bin/os.bin b/How_to_write_a_bootloader/Part_3/bootloader/bin/os.bin
index 8af68a948c1c2ad49063575f237794f12351808b..c073d45bfc5856eb4198f9e9d05c0c20f3ef56ca 100644
GIT binary patch
delta 135
zcmV;20C@j~D4i%A`nUi9j@XXCj?laSeEYNjumjByy8sZ5!@B?gkr5OOSbPs4zzhKo
zBEafikue?tK#@=$621Tc0RX=M01yDV01yBG{PU!-ZgT+%RjTOu0RRB&{<9GT_W>VO
piRFXr5XVLQ0Dubsi$(m#07#2P{DZ&(#sF!M$-}b|1oaP*kPD=TG|>P6

delta 100
zcmV-q0Gt1vD26C8`nUi9j@XXCj?laSeEYiq5VioafUyF#0JH+I2+b366Z#JU7EOE)
zAixX(4<f+oQ;|F#0X30Z9tP?F01yBOvk?M{0R>g6==%Y)Aq4#a233jWkX^&GAq4yn
Gk)Q;vc_nZF

diff --git a/How_to_write_a_bootloader/Part_3/bootloader/build/completeKernel.o b/How_to_write_a_bootloader/Part_3/bootloader/build/completeKernel.o
index cdbcae09cb07f20a04f73422d867238084f1b65d..f6296c8417b3885dd8f8b84769b963e6a6c577fb 100644
GIT binary patch
literal 3212
zcmeHIO>7%Q6n?ww4W>?9=ZBDzR@noAAe435Mo1|H(uUAfY6}8_K!D8JUOQIeU9(=d
zp+YoLg~X49K;i%bBrbr&g`yrfaDWOZ0*>4`gM<VZxb#5O@O`^G@g`LTm!9CQX5P>D
z=FQBTH?wCKjz6Gjnkdr5kgg`O_r@5Rj@X0@%T3BP;=gWeZf^c|Wt;7P<-d}FrI&v>
z_j}>ng$-HH$*T(+mt+zBxi9rg(s=#5ujJ_b{2^=N=*gu!to_sW0eedJA~kxHp3GK~
zuA~Ys#@_=L<HW|cJVoAyoQ#h~sj+sk9aM@dZs57Aw$pA(aoKOW#d6SDF5d69S3<v4
zocF74v0VvVx3Y4?_rq1+sk%XN(LY@Z{nF{65xOO(RPG`VIYC%DSWH<siJUzA$O-F!
zz5gzI>Y!-r@p8Dv$IwjCGW)=_ThR5=LQ>n9gRJM#X=abIY409~!C0ZSXNa=?Mktxg
z!;nlZiylBfz5%V!V`N9O<JmzIPPX)Gb3HLQo*&E^W20km>M7hzP`huBkw28XJ2#V~
zac<<y9&HfQOp7uf8`MXT=G~IZ9Rp(C3gO<I!PVV^rpxV&t^JknLmxd6$ham~Wg1=>
z9c5wUi7EXuydR|nCuoCX=#CJYHm18kK1b6b@76EU?|XLUAVM)S!{$)k%y-OP=xe4n
ztK(gQxd11;IGdVi&u4oxnU`Q=&5%?=59hNl>PPy_C%=IM>>aP&sC#bJsw_K!#5GcC
zIt@=ynb!QwOj4ZIWHan|?rh!l+@Mi`>I9YL*_P{tjZU)__||0IntX7|nrw&F*}B)k
z$jMp__0$d>uiEhHa;i~v{p(YE+Y?{8o|7awvMXI7O7Jzh?SBl^7``+a$z4`91GSMR
zLs-RKG9)f~WicfA2_*(YateyLA-y|v)^L}MsA|%Be^-HI$iTLLUPk`d97uUkABC>!
zi{88&iV7Tk)wM|8B9+6q;7X{JAjCk75FN!F-QOGHx@LXfMhyBCIrIoeI=Dks|Kvl|
zk(M_T`v>Ik`<NW*`GmYr<U+zfBgeQe$T99~a`^p_*ndj&KNCKk*vsUIQ%iU&;hlt^
zB}ZJmB%<w#?;>@v+s`#arwkqjF<(|vfG0Y1*Fv$YPUwhTZnwp*_{}CRn%G3EZn;x0
zIf3KVU0|`=>XbdFNxkdR@M^xoopL#FPo>e-hUcdBT7dD&9jj5|s$ba>F$9McU<d!2
z_<!P-c~+!3w0+&b!dCUMhFHnONozP~RyrQvXguF4>f?#7Zqd`JSb!p5@;lM!|4)8V
zEy0hR#CV)j5!cQ(n{Z`s!Ea6}DQpIEdLQf9hXosBG6!lO{FO1TqVw0-$1`x)>33NT
zN?}hyPS5*3=3Rr0^U|*7U4@*E_Yo50!=^}KFTkK=V#5gVmU2pAXCSBN9YNBWOU}!C
zspfqRays650K7+vcvhrW(9-c10Tf_kJic5i-aC*PPo3M(0G@@eh#1?430L-|?a%Ah
znm$eZR6P3qs0JmNikUvD2^^{gfNu`h$@P(Q532Sc$|BB#e|$xZMdE9l_In)ry%-^J
Hr~Li~I8J8H

literal 2928
zcmeHHO>7%g5T5ng#^A(q;sB|NgbxIQz-zbALt4_h2{atqAXHTqR8?57H@2yF*V<hp
zKuF|L2~NNXAt7;~M<h6K;D|(#xN_&f1;LdYQjy&6+kG!yJFVajV?EE`H}mGr&U^2_
zbn${=7^2A#Q>L28HxHzq=M%OrtMaIZCj5`TCzHvH<$vYB)PXA>{`T?pA7p2H`*eMM
zXZOm}^%E`Yq}7tg(1l#miTt!5sUgu*{}yEBhp#wA%2~)NKAlGuYc-?LY2I){-yK?Z
z<jL;&%a`gWtrMrL)+sR#6b#WE*}NR*f0AM0I>aFs^Kz?m6ko-kVHUN`_*{%7{FaSs
z(JZZ%Y6V~{Su)y;fMcyvE1Q+$6+ntr+yyw#9WyJZ%V)|PWg6S7pKcuk_6)PjQ;ah1
zR2K1{Tr-qn$dN+;B~nOgU%i&Q1MnscrmW%rNO%%0qI%#Y_q9-CI1;QBjI%l1VRebC
zNPrtUF~oSUw2;q#06SZskm|$vO6g{9Yq7BPBLHyVGuF2^Hq@7_H@tZ4yPG}Ncf)}L
z)efEh=E(Kq!PpyxLA}wdH(qJg8&TZd?D=CvHum>J*NtM^?+*N)s&vn@2mb8Q9clIh
z&uvBy;LeTai-9xtkT_~~f*>9ScGnG6t@mNGuN7Nn&LB-aUdn0;K4^x_nW1C+gBdUN
zhvxLfIlVHcFU{$-Ielg3ea*|ClVu=S6+aoi)65G?e;sx`pUdz+OI=ZwQAft<O>gwX
zbUxBSN!!1Nj}pe|UO5cMlgMM>jc<`7RWjx3&FAdsIeM9LNo1G2EOJ@#tBPMEN4!Ih
z7WS1rQ1&D*;z<iwI&XH571~w%H!_$=$-K}yZj~}V4QDyAS<yRQY<I+p;xOfXEroa~
zV)yM>tgao~Vs)ZOEGO_dX=2gabvxtUo*mkL&xH>rd)}5pM&piedkUi<1Ajl5iAfDA
zXQvaoZ)JBG4t#e8erQnn_CxG|T9cY^1}zQ)HuqoB<G^vA*mqJJtC+km)I`{K5}!x5
zyp2Wr3xmkd^e`6V`5sVD9wKmkyDnsM!JJ^ppTQ#jpK!^%0Y^?^zU)om-dxG^On{=-
zfNN_7oEQ@4C3_AYoM+@Y*aLlzi%M>Tld5oXma;g`=Nni$H$?gDKIgr858S&9P^5E=
zpl9n_$G&aYxG!HAUEhI{+u)==a4&#oajfqXES(#o)X?x93W~JvTj*M*>viA`C@9jt
zFQ8}ZyM=xA9PowH^?j}6HaO`k;8+jq(>Ut4v2<>T@+<b`{nf<Wr0=n^`+kRf`n&NZ
z)%*Sonfdg*tibURbWQYe{i3+Gf5`+H(lwE1Kj|&t>M%Y6JNIW8Icr1dhjbhF<GDj^
QdPdfo#r=eH{C*GIUBB4zh5!Hn

diff --git a/How_to_write_a_bootloader/Part_3/bootloader/build/kernel.asm.o b/How_to_write_a_bootloader/Part_3/bootloader/build/kernel.asm.o
index 42a9f409f6ae3ea95e9c92a08f0fff0f36534525..3afdb173ab92760179d1771916eed32418cadbbd 100644
GIT binary patch
literal 1968
zcmeHIJ8u&~5T3P@V5B5+0zybU<R&6CcMd^FNEGG~L;(m1QBa-k>`iRhzO(ku1ghi*
zP*5Nt3M42gscHOEQX<hL6$L2fo4Xx*Ll6=*jI}qfZ)bM)=Egf4_wOpDNJvqcrW#Sh
zI<Dq?m8vu^(7)mwlh>TxH7XGuI*F>*e!}9cN~0N~nkbI%4CIrJeGfQ}v4Dlp1eGdS
zm$95Qw9gKQ#CIJwk=f0-cfY}Hz~<(CHA}P#8|Q^M$@>Jd8*c>X1=xhd*Mvc2_U!@J
zV8N3366kK;8ZMIS<GjqJ-W|xY2O`zw!dU?^mgyzdpK#)P16-LmSmJn}MFAJw2grQy
zLi@n&LRrM(Bk=k7{d~l7;|=h_S6~y8c%NW!>wOQL)XNyD_sfs*c>MKHw*Tk<*bSUV
zy+z+~M-=4F74AKShU4B-0KNsc_`KBw>-ni^`dw{e-Sfh<PkuY;Yd<o>wtq*b-7FdS
zx09Ck)27k7*}at{SuY7&+W7a9?I25nZPUqg5C+lI^C&b~u<kn+PC^fFK7LTU;;mit
z>g%L--OncfRuoF%Da+@TbDw4%v*ES1gXN@_@LN{ZxpL)PWu<ZokdjABs=<YWZeW$@
z5}rzZUtGX5ANHtS(XpC&1I^~=Is3F;`UW)5eLly8yi7mO$ZP3nxD|vZjJI@3p24mC
zVk*?ZFp9%ILkhhUZze9h(CyYJGWwYyd!1Oj$U-lWn+7o_z@$lD+D<c*g%P9|{eoMa
zkCvZ#Qi3bUykXl69gJPy(SJgoTew|^%EbRxQz~OZEl<__-CaDQBipe{FM2NMhn<*$
RG(*ccTk`o@vhR}ZKLH6Vr#=7x

literal 1936
zcmeHIJ#W-N5S_J?a7ZM&1cV}iPzoXtg#(Bbd<X&(sQ^WyprAO}!3h`6POu#W6%l`c
z)YOy|6x8T`3MD1fK|0=B@A%e<ghUN<nw_t=Gh^?1?(O{ttHu~nG7`$z5?OJ9YgS&A
zuAETlUrFX9Pq|&g01DYr*U4j$e*NKu$bySeXzVm}gc|w=V;<Htm}wbfr<cIG2dc=V
zU7JN?H{em-27$ZRpvJLP`24zSz}<q6b(vc0K7sD%+eh#Wd`cQi;ZU8i&%oVLkQaLi
z-LLxtI6fcic3h11JFuUxdExMrh$X!T{|TqD55R@opo9bbsyd|NK0^17Q-;9p!#4xw
znX-4D@h7mKZw*17k&@>70>^Q6Lhb>_-ub-5Fdyyjzeb}G<bV1%-@sWsc75->ufw~D
zoHxc@INm?w#rVc<gWdl6>bZEdR2J(?FVZ4U2T@#R^62j4hYMGuE6dU4Wifk)(lC`J
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z^ls!x&vwV8ZFT->Z~(Ayj{Ef_s?yh$M9<P>ce584alV<B5*6tnKJ2R@JG)69XT;QY
zKi}AH;cJJ>mn22{N}+>(p0=R1qlRu2$l4&c*Ci^SmsL^43A8s^EuD?->bC6zwicZq
zbWX_6)@W$|vvCf&LvR^FJE_L$LQI%Nm_#wJ!EbIHw)5;<%LeMmA=G!Mm&N^DdSw+C
Rm271@=iNT$4LBej{RaNue+vKr

diff --git a/How_to_write_a_bootloader/Part_3/bootloader/build/kernel.o b/How_to_write_a_bootloader/Part_3/bootloader/build/kernel.o
index 77c100a8a832abca7929c86d8142c93e94c125ff..4f998f174f293f3b9cc20dcaeb1181a04734c6e4 100644
GIT binary patch
literal 2032
zcmcIlOK%%h6h3$C389m?NnDk_BpbvdNMsx!EK)EnO+#B$l?ob!K*$=~*Y+rxnJ_bM
z3PLJURjCylx?slwA-4R2vH&59V1>kQKw`m$9TJtw_sz_8CfUG-Bb|G`^SpD<J=eaz
ze(_bMlo(P{kzGyXuWIgD$;6`6WkEJ>|90b#xgXc>%g2s<vVQ-boX2|OTkD?qpZ@gy
zTL`s9Wr^w-lo?tKH40$W0F*sNl{WSHMXZ%g!l^^V)}2(U)i;1_HH{UHdG$oC?o=Ab
z8}n*mYVHvPx$4x>O6{ccqO<DIc>2hPM^zn_R>YVu)U6{T)q~<V7vQlU2YA`3@B>bO
zEtZzzoIvIaX}tor;d3F;roU^m6l@R}pkZm?yI>3Wp!FR+KXb9`VrP{P+lPjBZEPRF
zI<QsSLW9*fO#ES}`_10Si)B;Cq2B5Qo*&A&OB>C#)z#*+EADgda&sw2$DwWyb*N*%
z2i1#vqxQBAQ-2(6$5C@>*j#!YaY@>555qAsmj;7a>m>EUz8?<ds^8a<v_?^&Titj(
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z68Bp9=excCbCaS+*krPsoLgHv*<3`!o-VqDzR!UlfRw0@re~_vTev4)vLRmXE4AsH
z)|pxR-5(HO93{!?HB^;99~exz_jOR;TcIM^L{CyG^6&)b`OZFlW}jY@1BHd(y1+r3
z9JxFwB778lX0w#oc7gICk;8@L+f$gq$0%))rzjDZ4KwWRLf<GPzg$)F9!~O5?@8Jr
zmkaqqAx}}F4jz~Ag|g4o#Z5j4Qm+e{#<?6Bl<I4#xP346#O)@DxUt@H`?@<GcKmP<
z!IfdJ+l}?rve%2faH#hrZ26%!38-%%&7Dl|ML~d<QZ6%yy?{^lztV98avs<l5`PDI
zFNVylJPHFb+LzIrg*3v%@eX)z{}z|^+9X4=-a94T)O!XtPT1+f_YDeP2If29WRkhx
zOJI`&C|`s5(`v~0F2P_heH{KKK|#j%8uaqMGuViGk})cieLY~411JqBZxa+`eD6Uo
z*E@lFi?FdC?dBW-Fmsl{q#Y>l=P+C8BVQ||iTfSKU$cmOF>$x{#ofjH;y+?SChoH$
z&NzNST>hV!TljsXJK*v;&X)SZKOA!o*5y+%RK>l00c9R+&TGzYW`(g|LE-y0#5yGA
QmE*2pqc1a0zL>aw07ISqw*UYD

literal 1676
zcma)6y>HV{5Wg2EP)Hh@mXB6tFhik8#3_h@76SbMDj`(F(6Oo<=Ov9A+m-F0A|WA$
zO0WQ8VL?m`{1FHtA$CUo0sa7HhH^jqU2(I(N$2~%cX#iepWeBDS1CmTiY)po5q+{U
z%hi<3(m2&<{l(AM8(*O*rrKf}P}yLipDKus7+QG9jIvS@AN7t@P0ds%%2su{T2tdk
z#?BBG9J)1SRTs+F%kyO@7bo8?PqF)1#sZ_91Wr<eZ!%gm!(XL-S4a7qw!-x&rx8aU
z(YB5P-FLjSsnP_M(sU<F>Slo(RjX_3_R9RceR<Bg;>_7~KN$qN+0}uLdLD~z<ZU%~
zbddB0{!SFy^{!oiz<zPkZgztKN7g%?Nb5LpgLW_In)5b&w--=aLgS!<##ZR-M(nY>
zx81lMdIO&m$BkAPCjHQD>xgJ|Wo5yh<*F{4lF;QC<358T^<<<{EI#M{Fc|?%WT`r`
zS6Ch`Eq`MNG303ePK)$wKW7@caZEIux%gPD$%AF?U3Au=J3;(WF{RX^V?%OzNFE)M
zD|Fmw(AzjJ?_i7>lTA3=2E|Sl_EUUJ&CpYZVv7{Fa}IQb=)BR_jUM?`DVs6;u+^ZG
zpj-sz44Itxv7fjtrb(31E#VTqn~>9X6PKJ;9Fr6A#<g{8(B13>osdl_@3vZzew4Sm
zksEaNp@4ob&=SD;$?-xTYmyJ^M6R#7r2mC!cEtUoR{(kx9<uC4IwO|lwijT`f%siu
z9gp&#esk<2F-U`a*T5JM+a;E<A&W-;h35_a1S57Ci1ThRN({5a?}ZR6AhtDD2oKwP
zMjMO)vE5@ie=ZurTf@27U^&-iUSgP~&x}i842TUsz<j<j&WE~@4|>VxGmjX|2Y|=;
zD&?{dY`|SZ#qT96Co-4xD}H;%PfQ=!ko~VS4bBBTW6ak#nd=uXQ0hZoth~SvR(xjx
kv%x!qA9&=FU163!a?oio29O7UH<|aFW#LU~$v)!u2X7Le0RR91

diff --git a/How_to_write_a_bootloader/Part_3/bootloader/src/boot.asm b/How_to_write_a_bootloader/Part_3/bootloader/src/boot.asm
index a2d73ea..4e11386 100644
--- a/How_to_write_a_bootloader/Part_3/bootloader/src/boot.asm
+++ b/How_to_write_a_bootloader/Part_3/bootloader/src/boot.asm
@@ -18,10 +18,17 @@ start:
     mov ss, ax    ; Set stack segment (SS) to 0x00
     mov sp, 0x7c00; Set stack pointer (SP) to 0x7c00, top of the bootloader segment
     sti           ; Enable interrupts, allowing them to occur again
+
+    ; set video mode, al 03h is a text mode, this also clears the screen
+    mov AH, 00h
+    mov AL, 03h
+    int 0x10
     
 
 ;Load kernel
-mov bx, KERNEL_LOAD_SEG
+mov bx, KERNEL_LOAD_SEG ; Load segment
+mov es, bx
+mov bx, 0x0000 ; Load offset (SEG*16 + OFFSET)
 mov dh, 0x00
 mov dl, 0x80
 mov cl, 0x02
@@ -89,6 +96,13 @@ PModeMain:
     or al, 2
     out 0x92, al
 
+    ; Copy kernel from 0x10000 to 0x100000, where we jump to, as protected mode can access past 1MB now
+    mov esi, 0x10000  ; Source
+    mov edi, KERNEL_START_ADDR ; Destination
+    mov ecx, 4096     ; num sectors * 512 bytes
+    cld
+    rep movsb
+
     jmp CODE_OFFSET:KERNEL_START_ADDR
 
 
diff --git a/How_to_write_a_bootloader/Part_3/bootloader/src/kernel.asm b/How_to_write_a_bootloader/Part_3/bootloader/src/kernel.asm
index d8e5c35..c33f825 100644
--- a/How_to_write_a_bootloader/Part_3/bootloader/src/kernel.asm
+++ b/How_to_write_a_bootloader/Part_3/bootloader/src/kernel.asm
@@ -5,6 +5,6 @@ extern kernel_main
 
 _start:
     call kernel_main
-    jmp$
+    jmp $
 
-times 512-($ - $$) db 0
\ No newline at end of file
+times 510-($ - $$) db 0
\ No newline at end of file
diff --git a/How_to_write_a_bootloader/Part_3/bootloader/src/kernel.c b/How_to_write_a_bootloader/Part_3/bootloader/src/kernel.c
index 422e3a9..43824fc 100644
--- a/How_to_write_a_bootloader/Part_3/bootloader/src/kernel.c
+++ b/How_to_write_a_bootloader/Part_3/bootloader/src/kernel.c
@@ -1,5 +1,9 @@
 #include "kernel.h"
 
+#define VIDEO_MEMORY 0xb8000
+
 void kernel_main(){
-    
+    unsigned char *video = (unsigned char *)VIDEO_MEMORY;
+    video[0] = 'H';
+    video[2] = 'i';
 }
\ No newline at end of file
diff --git a/How_to_write_a_bootloader/Part_3/bootloader/src/kernel.h b/How_to_write_a_bootloader/Part_3/bootloader/src/kernel.h
index 846a76f..1b78527 100644
--- a/How_to_write_a_bootloader/Part_3/bootloader/src/kernel.h
+++ b/How_to_write_a_bootloader/Part_3/bootloader/src/kernel.h
@@ -1,5 +1,5 @@
-#ifndef KENREL_H
-#define KENREL_H
+#ifndef KERNEL_H
+#define KERNEL_H
 
 void kernel_main();
 
diff --git a/How_to_write_a_bootloader/Part_3/bootloader/src/linkerScript.ld b/How_to_write_a_bootloader/Part_3/bootloader/src/linkerScript.ld
index 895a479..4f94cc8 100644
--- a/How_to_write_a_bootloader/Part_3/bootloader/src/linkerScript.ld
+++ b/How_to_write_a_bootloader/Part_3/bootloader/src/linkerScript.ld
@@ -3,22 +3,22 @@ OUTPUT_FORMAT(binary)
 SECTIONS
 {
     . = 0x0100000;
-    .text : ALIGN(4096)
+    .text : ALIGN(16)
     {
         *(.text)
     }
 
-    .rodata : ALIGN(4096)
+    .rodata : ALIGN(16)
     {
         *(.rodata)
     }
 
-    .data : ALIGN(4096)
+    .data : ALIGN(16)
     {
         *(.data)
     }
 
-    .bss : ALIGN(4096)
+    .bss : ALIGN(16)
     {
         *(COMMON)
         *(.bss)