agent HDD() {
	private signal real q;
	private signal real srs;
	private signal real srsa;
	private signal real sps;
	private signal real spsa;
	private signal real power;
	private signal real requestlost;
	private signal real losttime;
	private signal real t;

	agent sr = SRequester();
	agent rq = Queue();
	agent sp = SProvider();
	agent pm = PowerManager();
}

agent SRequester() {
	output signal real srs;
	input signal real srsa;
	output signal real requestlost;
	output signal real losttime;
	output signal real t;
	
	mode srg = SReqOp();
}

mode SReqOp() {
	output signal real srs;
	output signal real requestlost;
	output signal real losttime;
	output signal real t;
	input signal real srsa;
	input signal real q;
	private signal real rl;
	private signal real lt;

	mode a = ActiveUser();
	mode pr = ProcessRequest();
	mode rl = ProcessRequest();

	trans Begin from default to a when true do { }
	sttrans a_pr from a when q<=20 distr randExp(1.383) to pr do {srs=1} weight 1
	sttrans a_pr from a when q==20 distr randExp(1.383) to rl do { rl=1; lt=t } weight 1
	trans pr_a from pr to a when srsa==1 do {srs=0}

	diff { d(t) == 1 }
	alge { requestlost == rl}
	alge { losttime == lt}
}

mode ActiveUser() {}
mode ProcessRequest() {}
mode RequestLost() {}

agent Queue() {
	mode qo = QueueOp()
}

mode QueueOp() {
	output signal real q;
	output signal real srsa;
	output signal real spsa;
	input signal real srs;
	input signal real sps;

	mode wr = WaitRequest();
	mode wsr = WaitForSR();
	mode wsp = WaitForSP();

	trans Begin from default to wr when true do {q=0}
	trans wr_wsr from wr to wsr when srs==1 do {q=q+1;srsa=1}
	trans wsr_wr from wsr to wr when srs==0 do {srsa=0}
	trans wr_wsp from wr to wsp when sps==1 do {q=q-1;spsa=1}
	trans wsp_wr from wsp to wr when sps==0 do {spsa=0}
}

mode WaitRequest() {}
mode WaitForSR() {}
mode WaitForSP() {}

agent SProvider() {
	mode spo = SProviderOp()
}

mode SProviderOp() {
	input signal real q;
	input signal real spsa;
	input signal real com;
	output signal real sps;
	output signal real state;
	output signal real power;

	mode i = Idle();
	mode b = Busy();
	mode sb = Standby();
	mode wspsa = WaitSPSA();
	mode isb = IdleStandby();
	mode sbi = StandbyIdle();

	trans Begin from default to i when true do {state=0}
	trans i_b from i to b when q>0 do {state=1}
	sttrans b_wspsa from b when true distr randExp(125) to wspsa do {sps=1; state=4} weight 1
	trans wspsa_i from wspsa to i when spsa==1 do {sps=0; state=0}
	trans i_isb from i to isb when com==1 do {state=5}
	sttrans isb_sb from isb when true distr randUniform(0.5,0.84) to sb do {state=2} weight 1
	trans sb_sbi from sb to sbi when com==0 do {state=6}
	sttrans sbi_i from sbi when true distr randUniform(0.73,2.5) to i do {state=0} weight 1
}

mode Idle() {
	output signal real power;
	diff {d(power)==0.95}
}

mode Busy() {
	output signal real power;
	diff {d(power)==2.15}
}

mode Standby() {
	output signal real power;
	diff {d(power)==0.13}
}

mode WaitSPSA() {
	output signal real power;
	diff {d(power)==0.95}
}

mode IdleStandby() {
	output signal real power;
	diff {d(power)==0.1}
}

mode StandbyIdle() {
	output signal real power;
	diff {d(power)==4.4}
}

agent PowerManager() {
	mode pmo = PowerManagerOp()
}

mode PowerManagerOp() {
	input signal real q;
	output signal real com;

	mode idle_com = IdleCommand();
	mode standby_com = StandbyCommand();

	trans Begin from default to idle_com when true do {com=0}
	trans toStandby from idle_com to standby_com when q==0 do {com=1}
	trans toIdle from standby_com to idle_com when q>=16 do {com=0}
}

mode IdleCommand() {}
mode StandbyCommand() {}